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CVE-2026-112891

Pillow: Quadratic GIF comment copying during save

6.9 MediumFix available

Pillow is a Python imaging library. From 9.2.0 until 13.0.0, Pillow performs quadratic copying when saving a GIF with a long comment. _get_global_header() repeatedly copies portions of comment data while assembling the global header, including comments retained from an untrusted input image. An attacker can supply an image with a large GIF comment to an application that saves it as GIF. This can consume excessive CPU and delay or deny service. This issue is fixed in version 13.0.0.

Attack profile

How easy it is to exploit

Attack vector: Network
Complexity: Low
Privileges needed: None
User interaction: None

What an attacker can affect

Confidentiality: None
Integrity: None
Availability: Low

Exploit likelihood

0.55%Up 0.2 points since Oct 20, 2026

What each source reports

CVE List Score used 6.9

Pillow: Quadratic GIF comment copying during save

Pillow is a Python imaging library. From 9.2.0 until 13.0.0, Pillow performs quadratic copying when saving a GIF with a long comment. _get_global_header() repeatedly copies portions of comment data while assembling the global header, including comments retained from an untrusted input image. An attacker can supply an image with a large GIF comment to an application that saves it as GIF. This can consume excessive CPU and delay or deny service. This issue is fixed in version 13.0.0.

Record: CVE-2026-112891
CVSS 4.0: 6.9 MediumCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N
Weakness: CWE-407
Updated: 2026-11-02

EUVDEUVD-2026-104649 6.9

Pillow is a Python imaging library. From 9.2.0 until 13.0.0, Pillow performs quadratic copying when saving a GIF with a long comment. _get_global_header() repeatedly copies portions of comment data while assembling the global header, including comments retained from an untrusted input image. An attacker can supply an image with a large GIF comment to an application that saves it as GIF. This can consume excessive CPU and delay or deny service. This issue is fixed in version 13.0.0.

Record: EUVD-2026-104649
CVSS 4.0: 6.9 MediumCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N
Updated: 2026-11-02

GitHub AdvisoriesGHSA-fc9g-5qg7-mf45 6.9

Pillow: Quadratic GIF comment copying during save

On Pillow 12.3.0 and upstream main (ad277e2761b489681e71b51e91367d46b0ceabb9), a GIF with a long comment makes _get_global_header() copy portions of the comment repeatedly when saving, including comments carried over from untrusted images. I suggest provisional Moderate severity for crafted-image CPU denial of service, with CVSS-B 6.9 assuming a network service automatically opens unauthenticated uploads and they are resaved as GIFs; impact depends on input-size, concurrency, and worker CPU limits.

Record: GHSA-fc9g-5qg7-mf45
CVSS 4.0: 6.9 MediumCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N
Weakness: CWE-407
Updated: 2026-11-02

NVD 6.9

Pillow is a Python imaging library. From 9.2.0 until 13.0.0, Pillow performs quadratic copying when saving a GIF with a long comment. _get_global_header() repeatedly copies portions of comment data while assembling the global header, including comments retained from an untrusted input image. An attacker can supply an image with a large GIF comment to an application that saves it as GIF. This can consume excessive CPU and delay or deny service. This issue is fixed in version 13.0.0.

Record: CVE-2026-112891
CVSS 4.0: 6.9 MediumCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/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: 7.5 HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Weakness: CWE-407
Updated: 2026-11-02

OSV 6.9

Pillow: Quadratic GIF comment copying during save

Pillow is a Python imaging library. From 9.2.0 until 13.0.0, Pillow performs quadratic copying when saving a GIF with a long comment. _get_global_header() repeatedly copies portions of comment data while assembling the global header, including comments retained from an untrusted input image. An attacker can supply an image with a large GIF comment to an application that saves it as GIF. This can consume excessive CPU and delay or deny service. This issue is fixed in version 13.0.0.

Record: CVE-2026-112891
CVSS 4.0: 6.9 MediumCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N
Weakness: CWE-407
Updated: 2026-11-03

OSVDEBIAN-CVE-2026-112891 7.5

Pillow is a Python imaging library. From 9.2.0 until 13.0.0, Pillow performs quadratic copying when saving a GIF with a long comment. _get_global_header() repeatedly copies portions of comment data while assembling the global header, including comments retained from an untrusted input image. An attacker can supply an image with a large GIF comment to an application that saves it as GIF. This can consume excessive CPU and delay or deny service. This issue is fixed in version 13.0.0.

Record: DEBIAN-CVE-2026-112891
CVSS 3.1: 7.5 HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Updated: 2026-11-02

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OSVGHSA-fc9g-5qg7-mf45 6.9

Pillow: Quadratic GIF comment copying during save

On Pillow 12.3.0 and upstream main (ad277e2761b489681e71b51e91367d46b0ceabb9), a GIF with a long comment makes _get_global_header() copy portions of the comment repeatedly when saving, including comments carried over from untrusted images. I suggest provisional Moderate severity for crafted-image CPU denial of service, with CVSS-B 6.9 assuming a network service automatically opens unauthenticated uploads and they are resaved as GIFs; impact depends on input-size, concurrency, and worker CPU limits.

Record: GHSA-fc9g-5qg7-mf45
CVSS 4.0: 6.9 MediumCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N
Weakness: CWE-407
Updated: 2026-11-02

OSVUBUNTU-CVE-2026-112891 6.9

Pillow is a Python imaging library. From 9.2.0 until 13.0.0, Pillow performs quadratic copying when saving a GIF with a long comment. _get_global_header() repeatedly copies portions of comment data while assembling the global header, including comments retained from an untrusted input image. An attacker can supply an image with a large GIF comment to an application that saves it as GIF. This can consume excessive CPU and delay or deny service. This issue is fixed in version 13.0.0.

Record: UBUNTU-CVE-2026-112891
CVSS 4.0: 6.9 MediumCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N
CVSS 3.1: 7.5 HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Updated: 2026-11-04

OSVBIT-pillow-2026-112891 No score

Pillow: Quadratic GIF comment copying during save

Pillow is a Python imaging library. From 9.2.0 until 13.0.0, Pillow performs quadratic copying when saving a GIF with a long comment. _get_global_header() repeatedly copies portions of comment data while assembling the global header, including comments retained from an untrusted input image. An attacker can supply an image with a large GIF comment to an application that saves it as GIF. This can consume excessive CPU and delay or deny service. This issue is fixed in version 13.0.0.

Record: BIT-pillow-2026-112891
Updated: 2026-11-02

OSVCLSA-2026-1793017750 No score

TuxCare security update for pillow (9 CVEs)

TuxCare rebuilt pillow to address 9 CVEs. Fixed in 11.3.0.post11+tuxcare.

Record: CLSA-2026-1793017750
Updated: 2026-11-02

OSVCLSA-2026-1793085879 No score

TuxCare security update for pillow (9 CVEs)

TuxCare rebuilt pillow to address 9 CVEs. Fixed in 11.2.1.post13+tuxcare.

Record: CLSA-2026-1793085879
Updated: 2026-11-02

OSVCLSA-2026-1793099358 No score

TuxCare security update for pillow (8 CVEs)

TuxCare rebuilt pillow to address 8 CVEs. Fixed in 10.4.0.post15+tuxcare.

Record: CLSA-2026-1793099358
Updated: 2026-11-02

OSVCLSA-2026-1793346161 No score

TuxCare security update for pillow (7 CVEs)

TuxCare rebuilt pillow to address 7 CVEs. Fixed in 9.5.0.post13+tuxcare.

Record: CLSA-2026-1793346161
Updated: 2026-11-02

OSVSUSE-SU-2026:5038-1 No score

Security update for python-Pillow

This update for python-Pillow fixes the following issues:

CVE-2026-96636: decompression-bomb protection bypass via multi-frame seek() in MPO and DCX (bsc#1286802).
CVE-2026-96637: decompression bomb check bypass in SpiderImagePlugin.seek() leads to unbounded allocation DoS (bsc#1286801).
CVE-2026-96640: PDF append accepts malformed shared page-tree DAG, which can cause resource exhaustion (bsc#1286798).
CVE-2026-96641: reachable undefined behavior in native integer operations can lead to denial of service or logic integrity compromise (bsc#1286797).
CVE-2026-96642: TarIO negative size field causes infinite CPU-spin loop (bsc#1286796).
CVE-2026-112390: Denial of Service via infinite loop during crafted MIC image parsing (bsc#1286256).
CVE-2026-112391: Denial of Service via unbounded recursion in PDF parser (bsc#1286273).
CVE-2026-112392: Denial of Service via zero-size images in rank filters (bsc#1286287).
CVE-2026-112393: heap buffer overflow and stale-heap disclosure in _tiffWriteProc when saving compressed TIFF data (bsc#1286325).
CVE-2026-112394: P;2L and P;4L decoders may read 1 to 3 bytes past the passed buffer size (bsc#1286311).
CVE-2026-112397: out-of-bounds access in _imagingmorph on a zero-width image (bsc#1286314).
CVE-2026-112398: heap buffer overflow in FPX JPEG decoding can lead to code execution (bsc#1286406).
CVE-2026-112399: Denial of service via crafted APNG image (bsc#1286368).
CVE-2026-112400: Denial of Service via memory exhaustion from crafted GIF image (bsc#1286370).
CVE-2026-112401: Denial of Service via crafted GIF comments (bsc#1286372).
CVE-2026-112402: Denial of service via double free during image transformation (bsc#1286381).
CVE-2026-112403: heap buffer overflow in ImagingJpegDecode allows for code execution (bsc#1286405).
CVE-2026-112405: NULL pointer dereference in Image.merge via an unvalidated band 0 (bsc#1286404).
CVE-2026-112406: infinite loop in PdfParser.rewrite_pages on page tree Parent cycle (bsc#1286403).
CVE-2026-112891: quadratic GIF comment copying during save (bsc#1286402).
CVE-2026-112892: MSP RLE decoder expands a tiny file into unbounded memory (bsc#1286401).
CVE-2026-112894: Denial of Service via crafted multi-frame image conversion (bsc#1286408).
CVE-2026-112895: Denial of service via crafted PDF during append operations (bsc#1286411).
CVE-2026-112896: TIFF encoder ColorMap plane-size mismatch causes a heap out-of-bounds read (bsc#1286400).
CVE-2026-112897: TiffDecode returns uninitialized memory as pixels for short JPEG strips (bsc#1286398).
CVE-2026-112899: EPS load(scale) lets Ghostscript render past the decompression bomb limit (bsc#1286489).
CVE-2026-112900: argument Injection in Ghostscript call can lead to remote code execution (bsc#1286397).
CVE-2026-112901: ReDoS in XbmImagePlugin can be triggered by 512-byte file (bsc#1286396).
CVE-2026-112902: memory disclosure and segfault in libtiff encoder via crafted TIFF tags (bsc#1286804).

Record: SUSE-SU-2026:5038-1
Updated: 2026-11-03

Affected products

Affected packages

Affected packages
Package	Affected	Fixed
`pillow` PyPI	9.2.0 up to 13.0.0	13.0.0
`pillow` Bitnami	9.2.0 up to 13.0.0	13.0.0
`pillow` TuxCare:PyPI From an advisory covering 9 CVEs	11.3.0 up to 11.3.0.post11+tuxcare, plus listed versions 11.3.0.post1+tuxcare11.3.0.post10+tuxcare11.3.0.post2+tuxcare11.3.0.post3+tuxcare11.3.0.post4+tuxcare Show 5 moreShow less 11.3.0.post5+tuxcare11.3.0.post6+tuxcare11.3.0.post7+tuxcare11.3.0.post8+tuxcare11.3.0.post9+tuxcare	11.3.0.post11+tuxcare
`pillow` TuxCare:PyPI From an advisory covering 9 CVEs	11.2.1 up to 11.2.1.post13+tuxcare, plus listed versions 11.2.1.post1+tuxcare11.2.1.post10+tuxcare11.2.1.post11+tuxcare11.2.1.post12+tuxcare11.2.1.post2+tuxcare Show 7 moreShow less 11.2.1.post3+tuxcare11.2.1.post4+tuxcare11.2.1.post5+tuxcare11.2.1.post6+tuxcare11.2.1.post7+tuxcare11.2.1.post8+tuxcare11.2.1.post9+tuxcare	11.2.1.post13+tuxcare
`pillow` TuxCare:PyPI From an advisory covering 8 CVEs	10.4.0 up to 10.4.0.post15+tuxcare, plus listed versions 10.4.0.post1+tuxcare10.4.0.post10+tuxcare10.4.0.post11+tuxcare10.4.0.post12+tuxcare10.4.0.post13+tuxcare Show 9 moreShow less 10.4.0.post14+tuxcare10.4.0.post2+tuxcare10.4.0.post3+tuxcare10.4.0.post4+tuxcare10.4.0.post5+tuxcare10.4.0.post6+tuxcare10.4.0.post7+tuxcare10.4.0.post8+tuxcare10.4.0.post9+tuxcare	10.4.0.post15+tuxcare
`pillow` TuxCare:PyPI From an advisory covering 7 CVEs	9.5.0 up to 9.5.0.post13+tuxcare, plus listed versions 9.5.0.post1+tuxcare9.5.0.post10+tuxcare9.5.0.post11+tuxcare9.5.0.post12+tuxcare9.5.0.post2+tuxcare Show 7 moreShow less 9.5.0.post3+tuxcare9.5.0.post4+tuxcare9.5.0.post5+tuxcare9.5.0.post6+tuxcare9.5.0.post7+tuxcare9.5.0.post8+tuxcare9.5.0.post9+tuxcare	9.5.0.post13+tuxcare
`pillow` Debian:12	All versions, plus listed versions 10.0.0-110.1.0-110.2.0-110.3.0-110.3.0-2 Show 19 moreShow less 10.4.0-110.4.0-1.111.1.0-111.1.0-211.1.0-311.1.0-411.1.0-511.2.1-111.3.0-112.0.0-112.1.0-112.1.1-112.1.1-212.2.0-112.3.0-113.0.0-19.4.0-1.19.4.0-1.1+deb12u19.5.0-1	None known
`pillow` Debian:13	All versions, plus listed versions 11.1.0-511.1.0-5+deb13u111.1.0-5+deb13u211.1.0-5+deb13u311.1.0-5+deb13u4 Show 9 moreShow less 11.2.1-111.3.0-112.0.0-112.1.0-112.1.1-112.1.1-212.2.0-112.3.0-113.0.0-1	None known
`pillow` Debian:14	All versions, plus listed versions 11.1.0-511.2.1-111.3.0-112.0.0-112.1.0-1 Show 5 moreShow less 12.1.1-112.1.1-212.2.0-112.3.0-113.0.0-1	None known
`pillow` PyPI	9.2.0 up to 13.0.0, plus listed versions 10.0.010.0.110.1.010.2.010.3.0 Show 13 moreShow less 10.4.011.0.011.1.011.2.111.3.012.0.012.1.012.1.112.2.012.3.09.3.09.4.09.5.0	13.0.0

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Affected packages
Package	Affected	Fixed
`python-Pillow` SUSE:Linux Enterprise Module for Package Hub 15 SP7 From an advisory covering 29 CVEs	before 7.2.0-150300.3.33.1	7.2.0-150300.3.33.1
`pillow-python2` Ubuntu:Pro:20.04:LTS	All versions, plus listed versions 6.2.1-3~build16.2.1-36.2.1-3ubuntu0.1~esm16.2.1-3ubuntu0.1~esm2	None known
`pillow` Ubuntu:24.04:LTS	All versions, plus listed versions 10.0.0-110.1.0-110.2.0-110.2.0-1build110.2.0-1ubuntu110.2.0-1ubuntu1.210.2.0-1ubuntu1.310.2.0-1ubuntu1.4	None known
`pillow` Ubuntu:26.10	All versions, plus listed versions 12.1.1-2ubuntu112.3.0-1ubuntu1	None known
`pillow` Ubuntu:26.04:LTS	All versions, plus listed versions 11.3.0-1ubuntu111.3.0-1ubuntu212.0.0-1ubuntu112.1.1-1ubuntu112.1.1-2ubuntu1 Show 4 moreShow less 12.1.1-2ubuntu1.112.1.1-2ubuntu1.212.1.1-2ubuntu1.312.1.1-2ubuntu1.4	None known

History

History
Recorded	Changed	Sources
Nov 6, 2026	affected
Nov 4, 2026	affected	OSV
Nov 4, 2026	affected, facts	OSV
Nov 3, 2026	affected, aliases, references	OSV
Nov 2, 2026	first indexed	CVE List, EUVD, GitHub Advisories, NVD, OSV

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

In short

CVE-2026-112891 is a medium vulnerability (CVSS 6.9) in Python Pillow, published October 19, 2026. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.55%, the 46th percentile. Fixed in pillow 13.0.0.

References

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