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CVE-2026-34589

OpenEXR: DWA Lossy Decoder Heap Out-of-Bounds Write

8.4 HighFix available

OpenEXR provides the specification and reference implementation of the EXR file format, an image storage format for the motion picture industry. From 3.2.0 to before 3.2.7, 3.3.9, and 3.4.9, the DWA lossy decoder constructs temporary per-component block pointers using signed 32-bit arithmetic. For a large enough width, the calculation overflows and later decoder stores operate on a wrapped pointer outside the allocated rowBlock backing store. This vulnerability is fixed in 3.2.7, 3.3.9, and 3.4.9.

Attack profile

How easy it is to exploit

Attack vector
Local
Complexity
Low
Privileges needed
None
User interaction
Active

What an attacker can affect

Confidentiality
High
Integrity
High
Availability
High

Exploit likelihood

0.43%Up 0.4 points since Apr 7, 2026
90%50%10%1%

What each source reports

CVE List Score used 8.4

OpenEXR: DWA Lossy Decoder Heap Out-of-Bounds Write

OpenEXR provides the specification and reference implementation of the EXR file format, an image storage format for the motion picture industry. From 3.2.0 to before 3.2.7, 3.3.9, and 3.4.9, the DWA lossy decoder constructs temporary per-component block pointers using signed 32-bit arithmetic. For a large enough width, the calculation overflows and later decoder stores operate on a wrapped pointer outside the allocated rowBlock backing store. This vulnerability is fixed in 3.2.7, 3.3.9, and 3.4.9.

Record
CVE-2026-34589
CVSS 4.0
8.4 HighCVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:A/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
CVSS 3.1
8.8 HighCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
Weakness
CWE-190, CWE-787, CWE-190
Updated
2026-11-02
EUVDEUVD-2026-19348 8.4

OpenEXR provides the specification and reference implementation of the EXR file format, an image storage format for the motion picture industry. From 3.2.0 to before 3.2.7, 3.3.9, and 3.4.9, the DWA lossy decoder constructs temporary per-component block pointers using signed 32-bit arithmetic. For a large enough width, the calculation overflows and later decoder stores operate on a wrapped pointer outside the allocated rowBlock backing store. This vulnerability is fixed in 3.2.7, 3.3.9, and 3.4.9.

Record
EUVD-2026-19348
CVSS 4.0
8.4 HighCVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:A/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
Updated
2026-11-02
GitHub AdvisoriesGHSA-p8xc-w3q4-h64x 8.4

OpenEXR: DWA Lossy Decoder Heap Out-of-Bounds Write

Summary

The DWA lossy decoder constructs temporary per-component block pointers using signed 32-bit arithmetic. For a large enough width, the calculation overflows and later decoder stores operate on a wrapped pointer outside the allocated rowBlock backing store.

This bug is reachable from the public decoder path and can be reproduced through the shipped exrcheck tool with a crafted scanline DWAA file. The confirmed dynamic symptom is a write-side crash in the lossy DCT execution path.

Tested on commit: 7820b7e1b93405ba1d551c43a945018226b75bc5

Root Cause and Data Flow

The vulnerable pointer construction lives in src/lib/OpenEXRCore/internal_dwa_decoder.h:

for (int comp = 1; comp < numComp; ++comp)
    rowBlock[comp] = rowBlock[comp - 1] + numBlocksX * 64;

The expression numBlocksX * 64 is computed as signed int. Once numBlocksX is large enough, the multiplication wraps, and rowBlock[comp] points backward rather than forward into the temporary decode buffer.

Later, LossyDctDecoder_execute() uses those derived pointers for real loads and stores during the block shuffle and reconstruction process. At that point the decoder is no longer operating within the bounds of the allocation created for rowBlockHandle.

The public control flow is the standard one:

InputFile / ScanLineInputFile public read
  -> exr_decoding_run(...)
     -> exr_uncompress_chunk(...)
        -> internal_exr_undo_dwaa(...)
           -> DwaCompressor_uncompress(...)
              -> LossyDctDecoder_execute(...)

UBSan gives a clean root-cause diagnosis on the overflowing multiply, while ASAN shows the later memory error in the write-side decode path.

Reproduction

dwa_scanline_exrcheck.zip

Build with exrcheck with ASAN and run:

❯ ./build-asan/bin/exrcheck /tmp/dwa_scanline_exrcheck.exr
 file /tmp/dwa_scanline_exrcheck.exr /home/pop/sec/openexr/src/lib/OpenEXRCore/internal_dwa_decoder.h:331:58: runtime error: signed integer overflow: 33554432 * 64 cannot be represented in type 'int'
AddressSanitizer:DEADLYSIGNAL
=================================================================
==1684058==ERROR: AddressSanitizer: SEGV on unknown address 0x758f8e5f0800 (pc 0x75979e850336 bp 0x7ffe8f1d3420 sp 0x7ffe8f1d30f0 T0)
==1684058==The signal is caused by a WRITE memory access.
    #0 0x75979e850336 in LossyDctDecoder_execute /home/pop/sec/openexr/src/lib/OpenEXRCore/internal_dwa_decoder.h:524
    #1 0x75979e879592 in DwaCompressor_uncompress /home/pop/sec/openexr/src/lib/OpenEXRCore/internal_dwa_compressor.h:1210
    #2 0x75979e879592 in internal_exr_undo_dwaa /home/pop/sec/openexr/src/lib/OpenEXRCore/internal_dwa.c:231
    #3 0x75979e95f878 in exr_uncompress_chunk /home/pop/sec/openexr/src/lib/OpenEXRCore/compression.c:542
    #4 0x75979e9659a8 in exr_decoding_run /home/pop/sec/openexr/src/lib/OpenEXRCore/decoding.c:580
    #5 0x7597a0271add in run_decode /home/pop/sec/openexr/src/lib/OpenEXR/ImfScanLineInputFile.cpp:586
    #6 0x7597a0283dc4 in Imf_4_0::ScanLineInputFile::Data::readPixels(Imf_4_0::FrameBuffer const&, int, int) /home/pop/sec/openexr/src/lib/OpenEXR/ImfScanLineInputFile.cpp:500
    #7 0x7597a00c6a81 in Imf_4_0::InputFile::Data::readPixels(int, int) /home/pop/sec/openexr/src/lib/OpenEXR/ImfInputFile.cpp:458
    #8 0x7597a13fe2dc in readScanline<Imf_4_0::InputPart> /home/pop/sec/openexr/src/lib/OpenEXRUtil/ImfCheckFile.cpp:239
    #9 0x7597a1405b04 in readMultiPart /home/pop/sec/openexr/src/lib/OpenEXRUtil/ImfCheckFile.cpp:905
    #10 0x7597a14126fd in runChecks<char const*> /home/pop/sec/openexr/src/lib/OpenEXRUtil/ImfCheckFile.cpp:1171
    #11 0x7597a14146b9 in Imf_4_0::checkOpenEXRFile(char const*, bool, bool, bool) /home/pop/sec/openexr/src/lib/OpenEXRUtil/ImfCheckFile.cpp:1835
    #12 0x61ba9582b8f8 in exrCheck(char const*, bool, bool, bool, bool) /home/pop/sec/openexr/src/bin/exrcheck/main.cpp:96
    #13…
Record
GHSA-p8xc-w3q4-h64x
CVSS 4.0
8.4 HighCVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:A/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
CVSS 3.1
5.0 MediumCVSS:3.1/AV:L/AC:L/PR:L/UI:R/S:U/C:N/I:N/A:H
Weakness
CWE-190, CWE-787
Updated
2026-11-02
NVD 8.4

OpenEXR provides the specification and reference implementation of the EXR file format, an image storage format for the motion picture industry. From 3.2.0 to before 3.2.7, 3.3.9, and 3.4.9, the DWA lossy decoder constructs temporary per-component block pointers using signed 32-bit arithmetic. For a large enough width, the calculation overflows and later decoder stores operate on a wrapped pointer outside the allocated rowBlock backing store. This vulnerability is fixed in 3.2.7, 3.3.9, and 3.4.9.

Record
CVE-2026-34589
CVSS 4.0
8.4 HighCVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:A/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
CVSS 3.1
5.0 MediumCVSS:3.1/AV:L/AC:L/PR:L/UI:R/S:U/C:N/I:N/A:H
CVSS 3.1
8.8 HighCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
Weakness
CWE-190, CWE-787
Updated
2026-11-02
OSVALPINE-CVE-2026-34589 5.0

OpenEXR provides the specification and reference implementation of the EXR file format, an image storage format for the motion picture industry. From 3.2.0 to before 3.2.7, 3.3.9, and 3.4.9, the DWA lossy decoder constructs temporary per-component block pointers using signed 32-bit arithmetic. For a large enough width, the calculation overflows and later decoder stores operate on a wrapped pointer outside the allocated rowBlock backing store. This vulnerability is fixed in 3.2.7, 3.3.9, and 3.4.9.

Record
ALPINE-CVE-2026-34589
CVSS 3.1
5.0 MediumCVSS:3.1/AV:L/AC:L/PR:L/UI:R/S:U/C:N/I:N/A:H
Updated
2026-11-03
OSVBELL-CVE-2026-34589 5.0
Record
BELL-CVE-2026-34589
CVSS 3.1
5.0 MediumCVSS:3.1/AV:L/AC:L/PR:L/UI:R/S:U/C:N/I:N/A:H
Updated
2026-11-02
Show 17 moreShow less
OSV 8.4

OpenEXR: DWA Lossy Decoder Heap Out-of-Bounds Write

OpenEXR provides the specification and reference implementation of the EXR file format, an image storage format for the motion picture industry. From 3.2.0 to before 3.2.7, 3.3.9, and 3.4.9, the DWA lossy decoder constructs temporary per-component block pointers using signed 32-bit arithmetic. For a large enough width, the calculation overflows and later decoder stores operate on a wrapped pointer outside the allocated rowBlock backing store. This vulnerability is fixed in 3.2.7, 3.3.9, and 3.4.9.

Record
CVE-2026-34589
CVSS 4.0
8.4 HighCVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:A/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
Weakness
CWE-190, CWE-787
Updated
2026-11-02
OSVDEBIAN-CVE-2026-34589 5.0

OpenEXR provides the specification and reference implementation of the EXR file format, an image storage format for the motion picture industry. From 3.2.0 to before 3.2.7, 3.3.9, and 3.4.9, the DWA lossy decoder constructs temporary per-component block pointers using signed 32-bit arithmetic. For a large enough width, the calculation overflows and later decoder stores operate on a wrapped pointer outside the allocated rowBlock backing store. This vulnerability is fixed in 3.2.7, 3.3.9, and 3.4.9.

Record
DEBIAN-CVE-2026-34589
CVSS 3.1
5.0 MediumCVSS:3.1/AV:L/AC:L/PR:L/UI:R/S:U/C:N/I:N/A:H
Updated
2026-11-02
OSVGHSA-p8xc-w3q4-h64x 8.4

OpenEXR: DWA Lossy Decoder Heap Out-of-Bounds Write

Summary

The DWA lossy decoder constructs temporary per-component block pointers using signed 32-bit arithmetic. For a large enough width, the calculation overflows and later decoder stores operate on a wrapped pointer outside the allocated rowBlock backing store.

This bug is reachable from the public decoder path and can be reproduced through the shipped exrcheck tool with a crafted scanline DWAA file. The confirmed dynamic symptom is a write-side crash in the lossy DCT execution path.

Tested on commit: 7820b7e1b93405ba1d551c43a945018226b75bc5

Root Cause and Data Flow

The vulnerable pointer construction lives in src/lib/OpenEXRCore/internal_dwa_decoder.h:

for (int comp = 1; comp < numComp; ++comp)
    rowBlock[comp] = rowBlock[comp - 1] + numBlocksX * 64;

The expression numBlocksX * 64 is computed as signed int. Once numBlocksX is large enough, the multiplication wraps, and rowBlock[comp] points backward rather than forward into the temporary decode buffer.

Later, LossyDctDecoder_execute() uses those derived pointers for real loads and stores during the block shuffle and reconstruction process. At that point the decoder is no longer operating within the bounds of the allocation created for rowBlockHandle.

The public control flow is the standard one:

InputFile / ScanLineInputFile public read
  -> exr_decoding_run(...)
     -> exr_uncompress_chunk(...)
        -> internal_exr_undo_dwaa(...)
           -> DwaCompressor_uncompress(...)
              -> LossyDctDecoder_execute(...)

UBSan gives a clean root-cause diagnosis on the overflowing multiply, while ASAN shows the later memory error in the write-side decode path.

Reproduction

dwa_scanline_exrcheck.zip

Build with exrcheck with ASAN and run:

❯ ./build-asan/bin/exrcheck /tmp/dwa_scanline_exrcheck.exr
 file /tmp/dwa_scanline_exrcheck.exr /home/pop/sec/openexr/src/lib/OpenEXRCore/internal_dwa_decoder.h:331:58: runtime error: signed integer overflow: 33554432 * 64 cannot be represented in type 'int'
AddressSanitizer:DEADLYSIGNAL
=================================================================
==1684058==ERROR: AddressSanitizer: SEGV on unknown address 0x758f8e5f0800 (pc 0x75979e850336 bp 0x7ffe8f1d3420 sp 0x7ffe8f1d30f0 T0)
==1684058==The signal is caused by a WRITE memory access.
    #0 0x75979e850336 in LossyDctDecoder_execute /home/pop/sec/openexr/src/lib/OpenEXRCore/internal_dwa_decoder.h:524
    #1 0x75979e879592 in DwaCompressor_uncompress /home/pop/sec/openexr/src/lib/OpenEXRCore/internal_dwa_compressor.h:1210
    #2 0x75979e879592 in internal_exr_undo_dwaa /home/pop/sec/openexr/src/lib/OpenEXRCore/internal_dwa.c:231
    #3 0x75979e95f878 in exr_uncompress_chunk /home/pop/sec/openexr/src/lib/OpenEXRCore/compression.c:542
    #4 0x75979e9659a8 in exr_decoding_run /home/pop/sec/openexr/src/lib/OpenEXRCore/decoding.c:580
    #5 0x7597a0271add in run_decode /home/pop/sec/openexr/src/lib/OpenEXR/ImfScanLineInputFile.cpp:586
    #6 0x7597a0283dc4 in Imf_4_0::ScanLineInputFile::Data::readPixels(Imf_4_0::FrameBuffer const&, int, int) /home/pop/sec/openexr/src/lib/OpenEXR/ImfScanLineInputFile.cpp:500
    #7 0x7597a00c6a81 in Imf_4_0::InputFile::Data::readPixels(int, int) /home/pop/sec/openexr/src/lib/OpenEXR/ImfInputFile.cpp:458
    #8 0x7597a13fe2dc in readScanline<Imf_4_0::InputPart> /home/pop/sec/openexr/src/lib/OpenEXRUtil/ImfCheckFile.cpp:239
    #9 0x7597a1405b04 in readMultiPart /home/pop/sec/openexr/src/lib/OpenEXRUtil/ImfCheckFile.cpp:905
    #10 0x7597a14126fd in runChecks<char const*> /home/pop/sec/openexr/src/lib/OpenEXRUtil/ImfCheckFile.cpp:1171
    #11 0x7597a14146b9 in Imf_4_0::checkOpenEXRFile(char const*, bool, bool, bool) /home/pop/sec/openexr/src/lib/OpenEXRUtil/ImfCheckFile.cpp:1835
    #12 0x61ba9582b8f8 in exrCheck(char const*, bool, bool, bool, bool) /home/pop/sec/openexr/src/bin/exrcheck/main.cpp:96
    #13…
Record
GHSA-p8xc-w3q4-h64x
CVSS 4.0
8.4 HighCVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:A/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
CVSS 3.1
5.0 MediumCVSS:3.1/AV:L/AC:L/PR:L/UI:R/S:U/C:N/I:N/A:H
Weakness
CWE-190, CWE-787
Updated
2026-11-02
OSVJLSEC-2026-149 8.4

OpenEXR provides the specification and reference implementation of the EXR file format, an image storage format for the motion picture industry. From 3.2.0 to before 3.2.7, 3.3.9, and 3.4.9, the DWA lossy decoder constructs temporary per-component block pointers using signed 32-bit arithmetic. For a large enough width, the calculation overflows and later decoder stores operate on a wrapped pointer outside the allocated rowBlock backing store. This vulnerability is fixed in 3.2.7, 3.3.9, and 3.4.9.

Record
JLSEC-2026-149
CVSS 4.0
8.4 HighCVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:A/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
CVSS 3.1
5.0 MediumCVSS:3.1/AV:L/AC:L/PR:L/UI:R/S:U/C:N/I:N/A:H
Updated
2026-11-02
OSVOESA-2026-1840 7.8

OpenEXR security update

OpenEXR is a high dynamic-range (HDR) image file format originally developed by Industrial Light &amp; Magic for use in computer imaging applications.

Security Fix(es):

OpenEXR provides the specification and reference implementation of the EXR file format, an image storage format for the motion picture industry. From 3.2.0 to before 3.2.7, 3.3.9, and 3.4.9, a misaligned memory write vulnerability exists in LossyDctDecoder_execute() in src/lib/OpenEXRCore/internal_dwa_decoder.h:749. When decoding a DWA or DWAB-compressed EXR file containing a FLOAT-type channel, the decoder performs an in-place HALF→FLOAT conversion by casting an unaligned uint8_t * row pointer to float * and writing through it. Because the row buffer may not be 4-byte aligned, this constitutes undefined behavior under the C standard and crashes immediately on architectures that enforce alignment (ARM, RISC-V, etc.). On x86 it is silently tolerated at runtime but remains exploitable via compiler optimizations that assume aligned access. This vulnerability is fixed in 3.2.7, 3.3.9, and 3.4.9.(CVE-2026-34379)

OpenEXR provides the specification and reference implementation of the EXR file format, an image storage format for the motion picture industry. From 3.2.0 to before 3.2.7, 3.3.9, and 3.4.9, a signed integer overflow exists in undo_pxr24_impl() in src/lib/OpenEXRCore/internal_pxr24.c at line 377. The expression (uint64_t)(w * 3) computes w * 3 as a signed 32-bit integer before casting to uint64_t. When w is large, this multiplication constitutes undefined behavior under the C standard. On tested builds (clang/gcc without sanitizers), two's-complement wraparound commonly occurs, and for specific values of w the wrapped result is a small positive integer, which may allow the subsequent bounds check to pass incorrectly. If the check is bypassed, the decoding loop proceeds to write pixel data through dout, potentially extending far beyond the allocated output buffer. This vulnerability is fixed in 3.2.7, 3.3.9, and 3.4.9.(CVE-2026-34380)

OpenEXR provides the specification and reference implementation of the EXR file format, an image storage format for the motion picture industry. From 3.1.0 to before 3.2.7, 3.3.9, and 3.4.9, internal_exr_undo_piz() advances the working wavelet pointer with signed 32-bit arithmetic. Because nx, ny, and wcount are int, a crafted EXR file can make this product overflow and wrap. The next channel then decodes from an incorrect address. The wavelet decode path operates in place, so this yields both out-of-bounds reads and out-of-bounds writes. This vulnerability is fixed in 3.2.7, 3.3.9, and 3.4.9.(CVE-2026-34588)

OpenEXR provides the specification and reference implementation of the EXR file format, an image storage format for the motion picture industry. From 3.2.0 to before 3.2.7, 3.3.9, and 3.4.9, the DWA lossy decoder constructs temporary per-component block pointers using signed 32-bit arithmetic. For a large enough width, the calculation overflows and later decoder stores operate on a wrapped pointer outside the allocated rowBlock backing store. This vulnerability is fixed in 3.2.7, 3.3.9, and 3.4.9.(CVE-2026-34589)

Record
OESA-2026-1840
CVSS 3.1
7.8 HighCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Updated
2026-11-02
OSVOESA-2026-1841 7.8

OpenEXR security update

OpenEXR is a high dynamic-range (HDR) image file format originally developed by Industrial Light &amp; Magic for use in computer imaging applications.

Security Fix(es):

OpenEXR provides the specification and reference implementation of the EXR file format, an image storage format for the motion picture industry. From 3.2.0 to before 3.2.7, 3.3.9, and 3.4.9, a misaligned memory write vulnerability exists in LossyDctDecoder_execute() in src/lib/OpenEXRCore/internal_dwa_decoder.h:749. When decoding a DWA or DWAB-compressed EXR file containing a FLOAT-type channel, the decoder performs an in-place HALF→FLOAT conversion by casting an unaligned uint8_t * row pointer to float * and writing through it. Because the row buffer may not be 4-byte aligned, this constitutes undefined behavior under the C standard and crashes immediately on architectures that enforce alignment (ARM, RISC-V, etc.). On x86 it is silently tolerated at runtime but remains exploitable via compiler optimizations that assume aligned access. This vulnerability is fixed in 3.2.7, 3.3.9, and 3.4.9.(CVE-2026-34379)

OpenEXR provides the specification and reference implementation of the EXR file format, an image storage format for the motion picture industry. From 3.2.0 to before 3.2.7, 3.3.9, and 3.4.9, a signed integer overflow exists in undo_pxr24_impl() in src/lib/OpenEXRCore/internal_pxr24.c at line 377. The expression (uint64_t)(w * 3) computes w * 3 as a signed 32-bit integer before casting to uint64_t. When w is large, this multiplication constitutes undefined behavior under the C standard. On tested builds (clang/gcc without sanitizers), two's-complement wraparound commonly occurs, and for specific values of w the wrapped result is a small positive integer, which may allow the subsequent bounds check to pass incorrectly. If the check is bypassed, the decoding loop proceeds to write pixel data through dout, potentially extending far beyond the allocated output buffer. This vulnerability is fixed in 3.2.7, 3.3.9, and 3.4.9.(CVE-2026-34380)

OpenEXR provides the specification and reference implementation of the EXR file format, an image storage format for the motion picture industry. From 3.1.0 to before 3.2.7, 3.3.9, and 3.4.9, internal_exr_undo_piz() advances the working wavelet pointer with signed 32-bit arithmetic. Because nx, ny, and wcount are int, a crafted EXR file can make this product overflow and wrap. The next channel then decodes from an incorrect address. The wavelet decode path operates in place, so this yields both out-of-bounds reads and out-of-bounds writes. This vulnerability is fixed in 3.2.7, 3.3.9, and 3.4.9.(CVE-2026-34588)

OpenEXR provides the specification and reference implementation of the EXR file format, an image storage format for the motion picture industry. From 3.2.0 to before 3.2.7, 3.3.9, and 3.4.9, the DWA lossy decoder constructs temporary per-component block pointers using signed 32-bit arithmetic. For a large enough width, the calculation overflows and later decoder stores operate on a wrapped pointer outside the allocated rowBlock backing store. This vulnerability is fixed in 3.2.7, 3.3.9, and 3.4.9.(CVE-2026-34589)

Record
OESA-2026-1841
CVSS 3.1
7.8 HighCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Updated
2026-11-02
OSVOESA-2026-1842 7.8

OpenEXR security update

OpenEXR is a high dynamic-range (HDR) image file format originally developed by Industrial Light &amp; Magic for use in computer imaging applications.

Security Fix(es):

OpenEXR provides the specification and reference implementation of the EXR file format, an image storage format for the motion picture industry. From 3.2.0 to before 3.2.7, 3.3.9, and 3.4.9, a misaligned memory write vulnerability exists in LossyDctDecoder_execute() in src/lib/OpenEXRCore/internal_dwa_decoder.h:749. When decoding a DWA or DWAB-compressed EXR file containing a FLOAT-type channel, the decoder performs an in-place HALF→FLOAT conversion by casting an unaligned uint8_t * row pointer to float * and writing through it. Because the row buffer may not be 4-byte aligned, this constitutes undefined behavior under the C standard and crashes immediately on architectures that enforce alignment (ARM, RISC-V, etc.). On x86 it is silently tolerated at runtime but remains exploitable via compiler optimizations that assume aligned access. This vulnerability is fixed in 3.2.7, 3.3.9, and 3.4.9.(CVE-2026-34379)

OpenEXR provides the specification and reference implementation of the EXR file format, an image storage format for the motion picture industry. From 3.2.0 to before 3.2.7, 3.3.9, and 3.4.9, a signed integer overflow exists in undo_pxr24_impl() in src/lib/OpenEXRCore/internal_pxr24.c at line 377. The expression (uint64_t)(w * 3) computes w * 3 as a signed 32-bit integer before casting to uint64_t. When w is large, this multiplication constitutes undefined behavior under the C standard. On tested builds (clang/gcc without sanitizers), two's-complement wraparound commonly occurs, and for specific values of w the wrapped result is a small positive integer, which may allow the subsequent bounds check to pass incorrectly. If the check is bypassed, the decoding loop proceeds to write pixel data through dout, potentially extending far beyond the allocated output buffer. This vulnerability is fixed in 3.2.7, 3.3.9, and 3.4.9.(CVE-2026-34380)

OpenEXR provides the specification and reference implementation of the EXR file format, an image storage format for the motion picture industry. From 3.1.0 to before 3.2.7, 3.3.9, and 3.4.9, internal_exr_undo_piz() advances the working wavelet pointer with signed 32-bit arithmetic. Because nx, ny, and wcount are int, a crafted EXR file can make this product overflow and wrap. The next channel then decodes from an incorrect address. The wavelet decode path operates in place, so this yields both out-of-bounds reads and out-of-bounds writes. This vulnerability is fixed in 3.2.7, 3.3.9, and 3.4.9.(CVE-2026-34588)

OpenEXR provides the specification and reference implementation of the EXR file format, an image storage format for the motion picture industry. From 3.2.0 to before 3.2.7, 3.3.9, and 3.4.9, the DWA lossy decoder constructs temporary per-component block pointers using signed 32-bit arithmetic. For a large enough width, the calculation overflows and later decoder stores operate on a wrapped pointer outside the allocated rowBlock backing store. This vulnerability is fixed in 3.2.7, 3.3.9, and 3.4.9.(CVE-2026-34589)

Record
OESA-2026-1842
CVSS 3.1
7.8 HighCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Updated
2026-11-02
OSVOESA-2026-1843 7.8

OpenEXR security update

OpenEXR is a high dynamic-range (HDR) image file format originally developed by Industrial Light &amp; Magic for use in computer imaging applications.

Security Fix(es):

OpenEXR provides the specification and reference implementation of the EXR file format, an image storage format for the motion picture industry. From 3.2.0 to before 3.2.7, 3.3.9, and 3.4.9, a misaligned memory write vulnerability exists in LossyDctDecoder_execute() in src/lib/OpenEXRCore/internal_dwa_decoder.h:749. When decoding a DWA or DWAB-compressed EXR file containing a FLOAT-type channel, the decoder performs an in-place HALF→FLOAT conversion by casting an unaligned uint8_t * row pointer to float * and writing through it. Because the row buffer may not be 4-byte aligned, this constitutes undefined behavior under the C standard and crashes immediately on architectures that enforce alignment (ARM, RISC-V, etc.). On x86 it is silently tolerated at runtime but remains exploitable via compiler optimizations that assume aligned access. This vulnerability is fixed in 3.2.7, 3.3.9, and 3.4.9.(CVE-2026-34379)

OpenEXR provides the specification and reference implementation of the EXR file format, an image storage format for the motion picture industry. From 3.2.0 to before 3.2.7, 3.3.9, and 3.4.9, a signed integer overflow exists in undo_pxr24_impl() in src/lib/OpenEXRCore/internal_pxr24.c at line 377. The expression (uint64_t)(w * 3) computes w * 3 as a signed 32-bit integer before casting to uint64_t. When w is large, this multiplication constitutes undefined behavior under the C standard. On tested builds (clang/gcc without sanitizers), two's-complement wraparound commonly occurs, and for specific values of w the wrapped result is a small positive integer, which may allow the subsequent bounds check to pass incorrectly. If the check is bypassed, the decoding loop proceeds to write pixel data through dout, potentially extending far beyond the allocated output buffer. This vulnerability is fixed in 3.2.7, 3.3.9, and 3.4.9.(CVE-2026-34380)

OpenEXR provides the specification and reference implementation of the EXR file format, an image storage format for the motion picture industry. From 3.1.0 to before 3.2.7, 3.3.9, and 3.4.9, internal_exr_undo_piz() advances the working wavelet pointer with signed 32-bit arithmetic. Because nx, ny, and wcount are int, a crafted EXR file can make this product overflow and wrap. The next channel then decodes from an incorrect address. The wavelet decode path operates in place, so this yields both out-of-bounds reads and out-of-bounds writes. This vulnerability is fixed in 3.2.7, 3.3.9, and 3.4.9.(CVE-2026-34588)

OpenEXR provides the specification and reference implementation of the EXR file format, an image storage format for the motion picture industry. From 3.2.0 to before 3.2.7, 3.3.9, and 3.4.9, the DWA lossy decoder constructs temporary per-component block pointers using signed 32-bit arithmetic. For a large enough width, the calculation overflows and later decoder stores operate on a wrapped pointer outside the allocated rowBlock backing store. This vulnerability is fixed in 3.2.7, 3.3.9, and 3.4.9.(CVE-2026-34589)

Record
OESA-2026-1843
CVSS 3.1
7.8 HighCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Updated
2026-11-02
OSVOESA-2026-1844 5.9

OpenEXR security update

OpenEXR is a high dynamic-range (HDR) image file format originally developed by Industrial Light &amp; Magic for use in computer imaging applications.

Security Fix(es):

OpenEXR provides the specification and reference implementation of the EXR file format, an image storage format for the motion picture industry. From 3.2.0 to before 3.2.7, 3.3.9, and 3.4.9, a signed integer overflow exists in undo_pxr24_impl() in src/lib/OpenEXRCore/internal_pxr24.c at line 377. The expression (uint64_t)(w * 3) computes w * 3 as a signed 32-bit integer before casting to uint64_t. When w is large, this multiplication constitutes undefined behavior under the C standard. On tested builds (clang/gcc without sanitizers), two's-complement wraparound commonly occurs, and for specific values of w the wrapped result is a small positive integer, which may allow the subsequent bounds check to pass incorrectly. If the check is bypassed, the decoding loop proceeds to write pixel data through dout, potentially extending far beyond the allocated output buffer. This vulnerability is fixed in 3.2.7, 3.3.9, and 3.4.9.(CVE-2026-34380)

OpenEXR provides the specification and reference implementation of the EXR file format, an image storage format for the motion picture industry. From 3.2.0 to before 3.2.7, 3.3.9, and 3.4.9, the DWA lossy decoder constructs temporary per-component block pointers using signed 32-bit arithmetic. For a large enough width, the calculation overflows and later decoder stores operate on a wrapped pointer outside the allocated rowBlock backing store. This vulnerability is fixed in 3.2.7, 3.3.9, and 3.4.9.(CVE-2026-34589)

Record
OESA-2026-1844
CVSS 3.1
5.9 MediumCVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:N/I:L/A:H
Updated
2026-11-02
OSVPYSEC-2026-2848 8.4

OpenEXR: DWA Lossy Decoder Heap Out-of-Bounds Write

Summary

The DWA lossy decoder constructs temporary per-component block pointers using signed 32-bit arithmetic. For a large enough width, the calculation overflows and later decoder stores operate on a wrapped pointer outside the allocated rowBlock backing store.

This bug is reachable from the public decoder path and can be reproduced through the shipped exrcheck tool with a crafted scanline DWAA file. The confirmed dynamic symptom is a write-side crash in the lossy DCT execution path.

Tested on commit: 7820b7e1b93405ba1d551c43a945018226b75bc5

Root Cause and Data Flow

The vulnerable pointer construction lives in src/lib/OpenEXRCore/internal_dwa_decoder.h:

for (int comp = 1; comp < numComp; ++comp)
    rowBlock[comp] = rowBlock[comp - 1] + numBlocksX * 64;

The expression numBlocksX * 64 is computed as signed int. Once numBlocksX is large enough, the multiplication wraps, and rowBlock[comp] points backward rather than forward into the temporary decode buffer.

Later, LossyDctDecoder_execute() uses those derived pointers for real loads and stores during the block shuffle and reconstruction process. At that point the decoder is no longer operating within the bounds of the allocation created for rowBlockHandle.

The public control flow is the standard one:

InputFile / ScanLineInputFile public read
  -> exr_decoding_run(...)
     -> exr_uncompress_chunk(...)
        -> internal_exr_undo_dwaa(...)
           -> DwaCompressor_uncompress(...)
              -> LossyDctDecoder_execute(...)

UBSan gives a clean root-cause diagnosis on the overflowing multiply, while ASAN shows the later memory error in the write-side decode path.

Reproduction

dwa_scanline_exrcheck.zip

Build with exrcheck with ASAN and run:

❯ ./build-asan/bin/exrcheck /tmp/dwa_scanline_exrcheck.exr
 file /tmp/dwa_scanline_exrcheck.exr /home/pop/sec/openexr/src/lib/OpenEXRCore/internal_dwa_decoder.h:331:58: runtime error: signed integer overflow: 33554432 * 64 cannot be represented in type 'int'
AddressSanitizer:DEADLYSIGNAL
=================================================================
==1684058==ERROR: AddressSanitizer: SEGV on unknown address 0x758f8e5f0800 (pc 0x75979e850336 bp 0x7ffe8f1d3420 sp 0x7ffe8f1d30f0 T0)
==1684058==The signal is caused by a WRITE memory access.
    #0 0x75979e850336 in LossyDctDecoder_execute /home/pop/sec/openexr/src/lib/OpenEXRCore/internal_dwa_decoder.h:524
    #1 0x75979e879592 in DwaCompressor_uncompress /home/pop/sec/openexr/src/lib/OpenEXRCore/internal_dwa_compressor.h:1210
    #2 0x75979e879592 in internal_exr_undo_dwaa /home/pop/sec/openexr/src/lib/OpenEXRCore/internal_dwa.c:231
    #3 0x75979e95f878 in exr_uncompress_chunk /home/pop/sec/openexr/src/lib/OpenEXRCore/compression.c:542
    #4 0x75979e9659a8 in exr_decoding_run /home/pop/sec/openexr/src/lib/OpenEXRCore/decoding.c:580
    #5 0x7597a0271add in run_decode /home/pop/sec/openexr/src/lib/OpenEXR/ImfScanLineInputFile.cpp:586
    #6 0x7597a0283dc4 in Imf_4_0::ScanLineInputFile::Data::readPixels(Imf_4_0::FrameBuffer const&, int, int) /home/pop/sec/openexr/src/lib/OpenEXR/ImfScanLineInputFile.cpp:500
    #7 0x7597a00c6a81 in Imf_4_0::InputFile::Data::readPixels(int, int) /home/pop/sec/openexr/src/lib/OpenEXR/ImfInputFile.cpp:458
    #8 0x7597a13fe2dc in readScanline<Imf_4_0::InputPart> /home/pop/sec/openexr/src/lib/OpenEXRUtil/ImfCheckFile.cpp:239
    #9 0x7597a1405b04 in readMultiPart /home/pop/sec/openexr/src/lib/OpenEXRUtil/ImfCheckFile.cpp:905
    #10 0x7597a14126fd in runChecks<char const*> /home/pop/sec/openexr/src/lib/OpenEXRUtil/ImfCheckFile.cpp:1171
    #11 0x7597a14146b9 in Imf_4_0::checkOpenEXRFile(char const*, bool, bool, bool) /home/pop/sec/openexr/src/lib/OpenEXRUtil/ImfCheckFile.cpp:1835
    #12 0x61ba9582b8f8 in exrCheck(char const*, bool, bool, bool, bool) /home/pop/sec/openexr/src/bin/exrcheck/main.cpp:96
    #13…
Record
PYSEC-2026-2848
CVSS 4.0
8.4 HighCVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:A/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
CVSS 3.1
5.0 MediumCVSS:3.1/AV:L/AC:L/PR:L/UI:R/S:U/C:N/I:N/A:H
Updated
2026-11-02
OSVROOT-OS-DEBIAN-11-CVE-2026-34589 5.0

CVE-2026-34589 in openexr - Patched by Root

Root has patched CVE-2026-34589 in the openexr package for Root:Debian:11. Multiple fixed versions available.

Record
ROOT-OS-DEBIAN-11-CVE-2026-34589
CVSS 3.1
5.0 MediumCVSS:3.1/AV:L/AC:L/PR:L/UI:R/S:U/C:N/I:N/A:H
Updated
2026-11-02
OSVROOT-OS-DEBIAN-12-CVE-2026-34589 5.0

CVE-2026-34589 in openexr - Patched by Root

Root has patched CVE-2026-34589 in the openexr package for Root:Debian:12. Multiple fixed versions available.

Record
ROOT-OS-DEBIAN-12-CVE-2026-34589
CVSS 3.1
5.0 MediumCVSS:3.1/AV:L/AC:L/PR:L/UI:R/S:U/C:N/I:N/A:H
Updated
2026-11-02
OSVROOT-OS-DEBIAN-13-CVE-2026-34589 5.0

CVE-2026-34589 in openexr - Patched by Root

Root has patched CVE-2026-34589 in the openexr package for Root:Debian:13. Multiple fixed versions available.

Record
ROOT-OS-DEBIAN-13-CVE-2026-34589
CVSS 3.1
5.0 MediumCVSS:3.1/AV:L/AC:L/PR:L/UI:R/S:U/C:N/I:N/A:H
Updated
2026-11-02
OSVUBUNTU-CVE-2026-34589 8.4

OpenEXR provides the specification and reference implementation of the EXR file format, an image storage format for the motion picture industry. From 3.2.0 to before 3.2.7, 3.3.9, and 3.4.9, the DWA lossy decoder constructs temporary per-component block pointers using signed 32-bit arithmetic. For a large enough width, the calculation overflows and later decoder stores operate on a wrapped pointer outside the allocated rowBlock backing store. This vulnerability is fixed in 3.2.7, 3.3.9, and 3.4.9.

Record
UBUNTU-CVE-2026-34589
CVSS 4.0
8.4 HighCVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:A/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
CVSS 3.1
8.8 HighCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
CVSS 3.1
5.0 MediumCVSS:3.1/AV:L/AC:L/PR:L/UI:R/S:U/C:N/I:N/A:H
Updated
2026-11-02
OSVopenSUSE-SU-2026:10505-1 No score

libIex-3_4-33-3.4.9-1.1 on GA media

These are all security issues fixed in the libIex-3_4-33-3.4.9-1.1 package on the GA media of openSUSE Tumbleweed.

Record
openSUSE-SU-2026:10505-1
Updated
2026-11-02
OSVopenSUSE-SU-2026:20605-1 No score

Security update for openexr

This update for openexr fixes the following issues:

  • CVE-2026-34379: misaligned memory write during file decoding can cause a denial of service (bsc#1261621).
  • CVE-2026-34380: lack of proper check can lead to integer overflow in image decoding (bsc#1261622).
  • CVE-2026-34588: crafted EXR file can lead to out of bound read and write (bsc#1261624).
  • CVE-2026-34589: crafted scanline DWAA file can lead to arbitrary code execution or denial of service (bsc#1261634).
Record
openSUSE-SU-2026:20605-1
Updated
2026-11-02
OSVSUSE-SU-2026:21372-1 No score

Security update for openexr

This update for openexr fixes the following issues:

  • CVE-2026-34379: misaligned memory write during file decoding can cause a denial of service (bsc#1261621).
  • CVE-2026-34380: lack of proper check can lead to integer overflow in image decoding (bsc#1261622).
  • CVE-2026-34588: crafted EXR file can lead to out of bound read and write (bsc#1261624).
  • CVE-2026-34589: crafted scanline DWAA file can lead to arbitrary code execution or denial of service (bsc#1261634).
Record
SUSE-SU-2026:21372-1
Updated
2026-11-02

Affected products

Affected packages

Affected packages
PackageAffectedFixed
openexr
PyPI
3.2.0 up to 3.2.7
3.2.7
openexr
PyPI
3.3.0 up to 3.3.9
3.3.9
openexr
PyPI
3.4.0 up to 3.4.9
3.4.9
openexr
Alpine:v3.22
3.2.0 up to 3.3.11-r0
3.3.11-r0
openexr
Alpine:v3.23
3.2.0 up to 3.4.13-r0
3.4.13-r0
openexr
Alpine:v3.24
3.2.0 up to 3.4.10-r0
3.4.10-r0
openexr
Alpaquita:stream
3.4.4-r0 up to 3.4.9-r0
3.4.9-r0
openexr
Debian:12
All versions, plus listed versions
3.1.13-13.1.13-23.1.5-53.1.5-5.13.1.5-5.1+hurd.1
Show 8 moreShow less
3.4.14-0.13.4.15+ds-13.4.16+ds-13.4.6+ds-13.4.6+ds-23.4.6+ds-33.4.6+ds-43.5.2+ds-1
None known
openexr
Debian:13
All versions, plus listed versions
3.1.13-23.4.14-0.13.4.15+ds-13.4.16+ds-13.4.6+ds-1
Show 4 moreShow less
3.4.6+ds-23.4.6+ds-33.4.6+ds-43.5.2+ds-1
None known
openexr
Debian:14
before 3.4.14-0.1, plus listed versions
3.1.13-23.4.6+ds-13.4.6+ds-23.4.6+ds-33.4.6+ds-4
3.4.14-0.1
Show 19 moreShow less
Affected packages
PackageAffectedFixed
openexr
PyPI
3.2.0 up to 3.2.7, plus listed versions
3.2.33.2.43.2.53.2.6
3.2.7
openexr
PyPI
3.3.0 up to 3.3.9, plus listed versions
3.3.13.3.23.3.33.3.43.3.53.3.63.3.73.3.8
3.3.9
openexr
PyPI
3.4.0 up to 3.4.9, plus listed versions
3.4.13.4.23.4.33.4.43.4.53.4.63.4.73.4.8
3.4.9
OpenEXR_jll
Julia
3.1.4+0 up to 3.4.9+0
3.4.9+0
OpenEXR
openEuler:24.03-LTS
From an advisory covering 4 CVEs
before 3.1.11-7.oe2403
3.1.11-7.oe2403
OpenEXR
openEuler:24.03-LTS-SP1
From an advisory covering 4 CVEs
before 3.1.11-7.oe2403sp1
3.1.11-7.oe2403sp1
OpenEXR
openEuler:24.03-LTS-SP2
From an advisory covering 4 CVEs
before 3.1.11-7.oe2403sp2
3.1.11-7.oe2403sp2
OpenEXR
openEuler:24.03-LTS-SP3
From an advisory covering 4 CVEs
before 3.1.11-7.oe2403sp3
3.1.11-7.oe2403sp3
OpenEXR
openEuler:22.03-LTS-SP4
From an advisory covering 2 CVEs
before 3.1.5-6.oe2203sp4
3.1.5-6.oe2203sp4
openexr
PyPI
3.2.0 up to 3.2.7, 3.3.0 up to 3.3.9, 3.4.0 up to 3.4.9, plus listed versions
3.2.33.2.43.2.53.2.63.3.1
Show 15 moreShow less
3.3.23.3.33.3.43.3.53.3.63.3.73.3.83.4.13.4.23.4.33.4.43.4.53.4.63.4.73.4.8
3.2.73.3.93.4.9
openexr
Root:Debian:11
before 2.5.4-2+deb11u1.aikido.17
2.5.4-2+deb11u1.aikido.172.5.4-2+deb11u1.aikido.162.5.4-2+deb11u1.root.io.152.5.4-2+deb11u1.aikido.18
rootio-openexr
Root:Debian:11
before 2.5.4-2+deb11u1.aikido.17
2.5.4-2+deb11u1.aikido.172.5.4-2+deb11u1.aikido.162.5.4-2+deb11u1.root.io.152.5.4-2+deb11u1.aikido.18
openexr
Root:Debian:12
before 3.1.5-5.root.io.21
3.1.5-5.root.io.213.1.5-5.root.io.223.1.5-5.root.io.233.1.5-5.root.io.163.1.5-5.root.io.173.1.5-5.root.io.183.1.5-5.root.io.193.1.5-5.root.io.203.1.5-5.aikido.243.1.5-5.aikido.25
rootio-openexr
Root:Debian:12
before 3.1.5-5.root.io.21
3.1.5-5.root.io.213.1.5-5.root.io.223.1.5-5.root.io.233.1.5-5.root.io.163.1.5-5.root.io.173.1.5-5.root.io.183.1.5-5.root.io.193.1.5-5.root.io.203.1.5-5.aikido.243.1.5-5.aikido.25
openexr
Root:Debian:13
before 3.1.13-2.aikido.14
3.1.13-2.aikido.143.1.13-2.root.io.113.1.13-2.root.io.133.1.13-2.root.io.123.1.13-2.aikido.15
rootio-openexr
Root:Debian:13
before 3.1.13-2.aikido.14
3.1.13-2.aikido.143.1.13-2.root.io.113.1.13-2.root.io.133.1.13-2.root.io.123.1.13-2.aikido.15
openexr
Ubuntu:26.10
All versions, plus listed versions
3.1.13-2build13.4.6+ds-4ubuntu3
None known
openexr
openSUSE:Tumbleweed
From an advisory covering 8 CVEs
before 3.4.9-1.1
3.4.9-1.1
openexr
openSUSE:Leap 16.0
From an advisory covering 4 CVEs
before 3.2.2-160000.6.1
3.2.2-160000.6.1

History

History
RecordedChangedSources
affected, facts
affected, aliases, referencesOSV
first indexedCVE List, EUVD, GitHub Advisories, NVD, OSV

Dates are when Every CVE recorded each change. Upstream dates may differ.

In short

CVE-2026-34589 is a high vulnerability (CVSS 8.4) in Academysoftwarefoundation Openexr, published April 6, 2026. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.43%, the 37th percentile. Fixed in openexr 3.2.7.

References

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Left out here: the rest of 3 source descriptions. The JSON record has them.

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