Connect your agent
AdvisoriesCriticalCheck your lockfilePluginHow it worksPricing Connect your agent

Advisory record · GHSA-g842-9rc4-69pw

Pillow: Decompression bomb check bypass in SpiderImagePlugin.seek() leads to unbounded allocation DoS

CVSS 7.1 HighEPSS 0.0037 · 31st percentile

Published by the GitHub Advisory Database at 22 Oct 2026, 15:57 UTC. agentprime has not analysed this yet, so whether it affects any app is not known.

PackageEcosystemAffectedFixed in
pillowPyPI<13.0.013.0.0
Identifiers
GHSA-g842-9rc4-69pw · BIT-pillow-2026-96637 · CVE-2026-96637 · PYSEC-2026-4338
Weakness (CWE)
CWE-400 · CWE-409
Tags
Published
22 Oct 2026
Updated
29 Oct 2026

Machine-written summary

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

Pillow versions below 13.0.0 are affected through the SPIDER image plugin, where seek() can change an image's size without running the decompression bomb check. An attacker who supplies a crafted SPIDER stack file under 1 KB can cause a multi-gigabyte memory allocation when the image is loaded, leading to denial of service. The fix is to upgrade to Pillow 13.0.0 or later.

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

ScoreRatingCVSSVectorSource
7.1 High 4.0 CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N CNA (GitHub_M)
  • CISA KEV Not listed.
  • EPSS 0.0037, the 31st percentile, on 5 Nov 2026: FIRST’s estimate of the chance of exploitation in the next 30 days.

Timeline

  1. 31 Oct 2026, 14:07 UTC First seen by agentprime
  2. 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.