High 7.1Published Oct 21, 2026

CVE-2026-96637Pillow: Decompression bomb check bypass in SpiderImagePlugin.seek() leads to unbounded allocation DoS

Updated under an hour ago (Oct 27, 2026, 11:40 PM ET)

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It affects python-pillow Pillow and 1 other product. Add what you run to find out whether that includes you.

EPSS puts the chance of exploitation in the next 30 days at 0.43%, higher than 37% of scored CVEs.

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Every CVE for python-pillow Pillow

Exploited in the last 30 days

Pillow is a Python imaging library. Prior to 13.0.0, SpiderImageFile.seek() in src/PIL/SpiderImagePlugin.py reparses a later SPIDER stack frame and replaces self._size without rerunning Image._decompression_bomb_check(). A tiny file can use a safe first frame to pass Image.open() and then declare very large dimensions in a later mode F frame. Loading that frame allocates approximately four bytes per attacker-declared pixel and can consume multiple gigabytes of memory. This issue is fixed in version 13.0.0.

CVSS: 7.1 HIGH (v4.0, CNA)CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N
Weakness (CWE): CWE-400, CWE-409
Known exploited: Not in CISA's KEV catalog
EPSS (exploitation in the next 30 days): 0.43% (percentile 37)
Assigned by: GitHub_M
NVD analysis: Analyzed
Record last updated: Oct 23, 2026
First seen by InfoSec Signals: Oct 21, 2026

Affected products

Affected products

python-pillow Pillow python_pillow:pillow (from the name)	before 13.0.0	CNA record
python pillow python:pillow	before 13.0.0	NVD

References

References

https://github.com/python-pillow/Pillow/security/advisories/GHSA-g842-9rc4-69pw	x-refsource-confirm, vendor-advisory
https://github.com/python-pillow/Pillow/pull/10076	x-refsource-misc, issue-tracking
https://github.com/python-pillow/Pillow/commit/7cb0e02389d8aac2a60896a490f572db0b07b841	x-refsource-misc, patch
https://github.com/python-pillow/Pillow/releases/tag/13.0.0	x-refsource-misc, release-notes

The CVE record on cve.org NVD's entry

The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.