GHSA-4rr5-89j8-mwwm: pillow (CVE-2026-112396)

Package	Ecosystem	Affected	Fixed in
pillow	PyPI	>=11.3.0, <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 11.3.0 up to but not including 13.0.0 are affected by a heap use-after-free when saving an image as TIFF to an in-memory buffer. If libtiff rejects a tag during encoding, the output buffer is freed while the libtiff handle stays open, so a later close writes into the freed memory. An application that encodes attacker-influenced images to TIFF in memory can be crashed, and the source says it may also allow code execution. 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
5.9	Medium	3.1	CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H	CNA (GitHub_M)

CISA KEV Not listed.
EPSS 0.0069, the 53rd 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.