Pillow multi-frame loaders can reuse stale native image storage after mode transitions

[ Why it matters ]Priority signals

• Critical severity: CVSS 9.8

[ Description ]Official description

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 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.

[ Fixes ]Fixes and patches

• Pillow 13.0.0Fixed version · GitHub Advisories · pip package Pillow: upgrade to 13.0.0 or later (affected >= 11.0.0, < 13.0.0)

[ Packages ]Affected open-source packages

• Pillow pipAffected >= 11.0.0, < 13.0.0 · fixed in 13.0.0 · GHSA-v9pv-5gc8-w2m6

[ References ]References

• github.com/python-pillow/Pillow/commit/78d97d994579aef81aafe123773d525f40f2522a
• github.com/python-pillow/Pillow/pull/10105
• github.com/python-pillow/Pillow/releases/tag/13.0.0
• github.com/python-pillow/Pillow/security/advisories/GHSA-v9pv-5gc8-w2m6