CVE-2026-42311: Pillow: OOB Write with Invalid PSD Tile Extents (Integer Overflow)

Severity: high (CVSS 7.8 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.1% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-05-09 · updated 2026-07-24
Weakness: CWE-190

Description

Pillow is a Python imaging library. From version 10.3.0 to before version 12.2.0, processing a malicious PSD file could lead to memory corruption, potentially resulting in a crash or arbitrary code execution. This issue has been patched in version 12.2.0.

Affected products

python-pillow Pillow: from 10.3.0 before 12.2.0 — fixed in 12.2.0

How to fix

Upgrade to a fixed version: python-pillow Pillow 12.2.0. Check the vendor advisory for mitigations.

References

https://github.com/python-pillow/Pillow/commit/58f9a1d166dcb0c274807d4423522d205b0c35ea
https://github.com/python-pillow/Pillow/pull/9520
https://github.com/python-pillow/Pillow/releases/tag/12.2.0
https://github.com/python-pillow/Pillow/security/advisories/GHSA-pwv6-vv43-88gr

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