CVE-2026-96639: python pillow

CVSS 9.8 (critical) · published 2026-10-21

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.

Affected products (NVD): python pillow

Fixed in (NVD): 13.0.0

Weakness: CWE-125, CWE-787

Source: NVD CVE-2026-96639

References

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

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