{"id":"CVE-2026-96639","title":"Pillow multi-frame loaders can reuse stale native image storage after mode transitions","summary":"Pillow is a Python imaging library. From 11.0.0 until 13.0.0, multi-frame loaders can retain an ImagingCore allocation created for a narrow frame mode while a later frame of the same dimensions changes the logical mode and decoder tiles …","severity":"critical","cvss":9.8,"cvssVector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","cvssSource":"cna","cwe":["CWE-125","CWE-787"],"vendor":"python-pillow","product":"Pillow","affected":["Pillow >= 11.0.0, < 13.0.0"],"published":"2026-10-21","updated":"2026-10-21","sourceUpdated":"2026-10-21T21:06:42.111Z","source":"CVEORG","sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-96639","references":[{"url":"https://github.com/python-pillow/Pillow/security/advisories/GHSA-v9pv-5gc8-w2m6","label":"https://github.com/python-pillow/Pillow/security/advisories/GHSA-v9pv-5gc8-w2m6"},{"url":"https://github.com/python-pillow/Pillow/pull/10105","label":"https://github.com/python-pillow/Pillow/pull/10105"},{"url":"https://github.com/python-pillow/Pillow/commit/78d97d994579aef81aafe123773d525f40f2522a","label":"https://github.com/python-pillow/Pillow/commit/78d97d994579aef81aafe123773d525f40f2522a"},{"url":"https://github.com/python-pillow/Pillow/releases/tag/13.0.0","label":"https://github.com/python-pillow/Pillow/releases/tag/13.0.0"}],"tags":["cve.org"],"ingestedAt":"2026-10-21T22:18:33.756Z","slug":"CVE-2026-96639","body":"## Overview\n\nPillow is a Python imaging library. From 11.0.0 until 13.0.0, multi-frame loaders can retain an ImagingCore allocation created for a narrow frame mode while a later frame of the same dimensions changes the logical mode and decoder tiles to wider RGB or CMYK data. ImageFile.load_prepare() reuses the stale native storage because _im is non-null without verifying that its mode and size still match. Crafted PSD, MPO, DCX, or MIC frame transitions can then write wider pixels into the narrow allocation, causing native out-of-bounds writes and crashes. The MPO path can also cause a native over-read and, in demonstrated runtime-specific profiles, command execution. This issue is fixed in version 13.0.0.\n\n## Affected\n\n- `Pillow >= 11.0.0, < 13.0.0`\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.","depth":"midnight","depthScore":54,"depthScoreParts":{"impact":53.9,"likelihood":0,"exploitation":0,"ransomware":0},"changes":[]}