GHSA-4558-3h8r-v8xp: pillow (CVE-2026-112394)

Package	Ecosystem	Affected	Fixed in
pillow	PyPI	<13.0.0	13.0.0

Machine-written summary

Summary written by Claude Haiku from the source advisory. Not reviewed by a person.

Pillow versions before 13.0.0 have a bug in the P;2L and P;4L decoders, where the decoder's size check and the plane unpackers disagree about how many bytes a line needs. Using Image.frombytes() or Image.frombuffer() with particular width and height values, an attacker who can supply the image data can cause up to 1 or 3 bytes of memory past the caller's buffer to be read into the last decoded rows, and a crash is possible if the read reaches unmapped memory. Upgrade to Pillow 13.0.0 or later, which contains the fix.

Written 31 Oct 2026.

Not analysed yet

We haven’t published our analysis of this Advisory yet. Once a person has reviewed it, this page will say what’s vulnerable, what has to be true for your app to be affected, and how to check.

Severity and exploitation

Score	Rating	CVSS	Vector	Source
6.3	Medium	4.0	CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:L/VI:N/VA:L/SC:N/SI:N/SA:N	CNA (GitHub_M)

CISA KEV Not listed.
EPSS 0.0056, the 46th percentile, on 5 Nov 2026: FIRST’s estimate of the chance of exploitation in the next 30 days.

Timeline

31 Oct 2026, 14:07 UTC First seen by agentprime
31 Oct 2026, 14:07 UTC Confirmed by OSV

Sources

Facts on this page come from the GitHub Advisory Database (CC-BY 4.0), OSV and the other sources listed, as published. We don’t reproduce full advisory descriptions, which can contain exploit code.