Medium 6.5Published Oct 21, 2026

CVE-2026-96636Pillow: Decompression-bomb protection bypass via multi-frame seek() in MPO and DCX (MpoImageFile.seek / DcxImageFile.seek)

Updated under an hour ago (Oct 30, 2026, 5:30 AM 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.

No exploitation reported and no EPSS estimate yet.

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Pillow is a Python imaging library. Prior to 13.0.0, MpoImageFile.seek() and DcxImageFile.seek() reparse later MPO or DCX frames and replace self._size without rerunning Image._decompression_bomb_check(). A crafted multi-frame image can use a tiny first frame to pass Image.open() and then declare an over-limit later frame. Normal frame iteration through seek(), load(), or ImageSequence.Iterator can decode that frame and commit hundreds of megabytes or more, causing memory-exhaustion denial of service. This issue is fixed in version 13.0.0.

CVSS: 6.5 MEDIUM (v3.1, CNA)CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H
Weakness (CWE): CWE-400, CWE-409
Known exploited: Not in CISA's KEV catalog
EPSS (exploitation in the next 30 days): Not loaded for this CVE
Assigned by: GitHub_M
NVD analysis: Analyzed
Record last updated: Oct 21, 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-p8hx-v2p6-rp84	x-refsource-confirm, vendor-advisory
https://github.com/python-pillow/Pillow/pull/10011	x-refsource-misc, issue-tracking
https://github.com/python-pillow/Pillow/commit/f1acfc54c53502948d0d14121872061df931db48	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.