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Vulnerability · Published Oct 21, 2026 · Assigned by GitHub_M

CVE-2026-96636Pillow: Decompression-bomb protection bypass via multi-frame seek() in MPO and DCX (MpoImageFile.seek / DcxImageFile.seek)

Medium 6.5

In plain English

A medium-severity uncontrolled resource consumption in Pillow from python-pillow. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 0.3% (higher than 28% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS 3.1)6.5Medium
Exploit odds (30 days)0.3%top 71.9% of all CVEs
Exploited in the wildNo reportsCISA SSVC: poc
Attack toolingNoneno public tooling known

Official description

Pillow is a Python imaging library. Prior to 13.0.0, MpoImageFile.seek() and DcxImageFile.seek() reparse later MPO or DCX frames and replace self._size without rerunning Image._decompression_bomb_check(). A crafted multi-frame image can use a tiny first frame to pass Image.open() and then declare an over-limit later frame. Normal frame iteration through seek(), load(), or ImageSequence.Iterator can decode that frame and commit hundreds of megabytes or more, causing memory-exhaustion denial of service. This issue is fixed in version 13.0.0.

Affected packages & fixed versions

EcosystemPackageFixed inAdvisory
Debian:12pillowno fix listedDEBIAN-CVE-2026-96636
Debian:13pillowno fix listedDEBIAN-CVE-2026-96636
Debian:14pillowno fix listedDEBIAN-CVE-2026-96636
PyPIpillow13.0.0GHSA-p8hx-v2p6-rp84
PyPIpillow13.0.0PYSEC-2026-4337
Ubuntu:22.04:LTSpillowno fix listedUBUNTU-CVE-2026-96636
Ubuntu:24.04:LTSpillowno fix listedUBUNTU-CVE-2026-96636
Ubuntu:26.04:LTSpillowno fix listedUBUNTU-CVE-2026-96636
Ubuntu:26.10pillowno fix listedUBUNTU-CVE-2026-96636

Affected products (as reported)

VendorProductVersions
python-pillow Pillow < 13.0.0

Weakness: CWE-400, CWE-409 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H

References