GHSA-8g5g-8vmr-9782: pillow (CVE-2026-112403)

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 are affected by a heap buffer overflow in the JPEG decoder (ImagingJpegDecode). A specially crafted lossless (SOF3) JPEG file, when processed through the thumbnail path that calls draft(), causes writes past a heap allocation, so an attacker who can supply an image file can likely cause memory corruption. Upgrade to Pillow 13.0.0 or later, which contains the fix; avoiding thumbnail() with reducing_gap=None or calling load() first is a workaround noted in the source.

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
9.2	Critical	4.0	CVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N	CNA (GitHub_M)

CISA KEV Not listed.
EPSS 0.0095, the 61st percentile, on 8 Nov 2026: FIRST’s estimate of the chance of exploitation in the next 30 days.

Timeline

17 Oct 2026, 10:34 UTC Published by the maintainers as a GitHub repository advisory
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.