Pillow: Double free in ImagingScaleAffine on calloc failure via Image.transform

[ Why it matters ]Priority signals

• Public proof-of-concept exploit exists (CISA SSVC)

[ Description ]Official description

Pillow is a Python imaging library. Prior to 13.0.0, Pillow can double free image memory when ImagingScaleAffine encounters a selective allocation failure. The affected fast path handles Transform.EXTENT or pure scale-and-translate Transform.AFFINE operations with the default NEAREST resampling. The output image allocation must succeed while the additional per-column lookup allocation fails, after which the error path deletes image storage that later cleanup releases again. An attacker who can drive such a large Image.transform() operation under memory pressure may trigger the failure. This can crash the process and may corrupt memory. 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 <= 12.3.0)

[ Packages ]Affected open-source packages

• Pillow pipAffected <= 12.3.0 · fixed in 13.0.0 · GHSA-7mwm-ghpf-9vrm

[ References ]References

• github.com/python-pillow/Pillow/commit/aafa6c75f7cdabb9f409a8aac7c780bea31d08d9
• github.com/python-pillow/Pillow/releases/tag/13.0.0
• github.com/python-pillow/Pillow/security/advisories/GHSA-7mwm-ghpf-9vrm