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Vulnerability · Published Oct 21, 2026 · Assigned by GitHub_M

CVE-2026-96643Pillow: PNG eXIf chunk makes EXIF parsing run in quadratic time

High 7.1

In plain English

A high-severity security flaw in Pillow from python-pillow. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.4% (higher than 31% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS 4.0)7.1High
Exploit odds (30 days)0.4%top 68.6% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack toolingNoneno public tooling known

Official description

Pillow is a Python imaging library. From 11.0.0 until 13.0.0, Exif.load() in src/PIL/Image.py repeatedly slices the remaining EXIF data while it begins with the six-byte Exif header. src/PIL/PngImagePlugin.py accepts an uncapped PNG eXIf chunk, so a file filled with repeated headers causes a new shrinking copy on every iteration and quadratic CPU work. The condition is reachable through Image.getexif(), Image._getexif(), and ImageOps.exif_transpose(), including common photo-upload rotation workflows. This issue is fixed in version 13.0.0.

Affected packages & fixed versions

EcosystemPackageFixed inAdvisory
Debian:12pillowno fix listedDEBIAN-CVE-2026-96643
Debian:13pillowno fix listedDEBIAN-CVE-2026-96643
Debian:14pillowno fix listedDEBIAN-CVE-2026-96643
PyPIpillow13.0.0PYSEC-2026-4342
PyPIpillow13.0.0GHSA-g4qv-2jxx-769h
Ubuntu:26.04:LTSpillowno fix listedUBUNTU-CVE-2026-96643
Ubuntu:26.10pillowno fix listedUBUNTU-CVE-2026-96643

Affected products (as reported)

VendorProductVersions
python-pillow Pillow >= 11.0.0, < 13.0.0

Weakness: CWE-407 · Vector: 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

References