Description
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.
Affected products
python: pillow
References5
- github.com/python-pillow/Pillow/security/advisories/GHSA-p8hx-v… Vendor Advisory
- github.com/python-pillow/Pillow/security/advisories/GHSA-p8hx-v… Vendor Advisory
- github.com/python-pillow/Pillow/commit/f1acfc54c53502948d0d1412… Patch
- github.com/python-pillow/Pillow/pull/10011 Issue Tracking
- github.com/python-pillow/Pillow/releases/tag/13.0.0 Release Notes
Metrics
- CVSS 3.1
-
6.5
MEDIUM
Score source: CNA
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H - EPSS — exploit probability
- 0% percentile: 28 · as of 8 November 2026
- CWE
- CWE-400CWE-409
Could this be exploited in your environment?
A patch closes the known hole. A penetration test shows what an attacker can still reach — with proof.