PYSEC-2026-4339

At a glance

Published
Updated
CVE
CVE-2026-96639
Aliases
GHSA-v9pv-5gc8-w2m6
CVSS_V3
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

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.

Affected packages

PackageVersions
PyPI · pillowintroduced 11.0.0, fixed 13.0.0

References

Sources

SourceLicence
OSV.devCC-BY 4.0 — PyPA Advisory Database