Pillow is a Python imaging library. From 8.1.0 until 13.0.0, Pillow can allocate an APNG disposal background at the full canvas size before applying the decompression-bomb check. A crafted APNG with a small first frame, a very large declared canvas, and background disposal or first-frame OP_PREVIOUS reaches PngImageFile._seek while Image.open() positions frame zero. The full-canvas allocation occurs inside Image.open() without requiring pixel loading or frame iteration. This can exhaust memory and deny service. This issue is fixed in version 13.0.0.
Fix
Patch, vendor advisory and mitigation references on NVD 3
- https://github.com/python-pillow/Pillow/commit/f1acfc54c53502948d0d14121872061df931db48 Patch
- https://github.com/python-pillow/Pillow/security/advisories/GHSA-5xm2-6676-qcp9 Exploit, Mitigation, Patch, Vendor Advisory
- https://github.com/python-pillow/Pillow/security/advisories/GHSA-5xm2-6676-qcp9 Exploit, Mitigation, Patch, Vendor Advisory
Every line above is quoted from NVD, CISA, Microsoft, the vendor's own advisory or DISA; nothing is generated.
Change history 6
- StatusAnalyzed → ModifiedNVD modified 2026-10-28 16:17
- Cpes+1 CPE criteria (now 1)NVD modified 2026-10-27 21:02
- StatusUndergoing Analysis → AnalyzedNVD modified 2026-10-27 21:02
- StatusPublished → Undergoing AnalysisNVD modified 2026-10-20 19:48
- StatusReceived → PublishedNVD modified 2026-10-19 21:10
- First seenCVSS 8.7NVD modified 2026-10-19 22:17
Affected (CPE criteria) 1
cpe:2.3:a:python:pillow:*:*:*:*:*:*:*:*
References 4
- https://github.com/python-pillow/Pillow/commit/f1acfc54c53502948d0d14121872061df931db48 Patch
- https://github.com/python-pillow/Pillow/releases/tag/13.0.0 Release Notes
- https://github.com/python-pillow/Pillow/security/advisories/GHSA-5xm2-6676-qcp9 Exploit, Mitigation, Patch, Vendor Advisory
- https://github.com/python-pillow/Pillow/security/advisories/GHSA-5xm2-6676-qcp9 Exploit, Mitigation, Patch, Vendor Advisory