What’s Vulnerable › Vulnerabilities

CVE-2026-112401: Pillow: Quadratic GIF comment concatenation allows DoS in Image.open()

• Severity: high (CVSS 7.5 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.5% probability of exploitation in the next 30 days
• Public exploit or detection template: yes
• Published: 2026-10-19 · updated 2026-10-27
• Weakness: CWE-407

Description

Pillow is a Python imaging library. From 5.4.0 until 13.0.0, Pillow performs quadratic copying while parsing GIF comments. GifImageFile._seek() repeatedly appends immutable bytes for comment sub-blocks and multiple comment extensions, and frame zero is parsed during Image.open(). An attacker can submit a small-dimension GIF containing many comment extensions to any application that opens the file. This can consume excessive CPU and deny service before the application can inspect the image. This issue is fixed in version 13.0.0.

Affected products

• python-pillow Pillow: from 5.4.0 before 13.0.0 — fixed in 13.0.0
• Pypi Pillow: from 5.4.0 before 13.0.0; 10.0.0, 10.0.1, 10.1.0, 10.2.0, 10.3.0, 10.4.0 (+39) — fixed in 13.0.0
• python-pillow Pillow: from 5.4.0, < 13.0.0

How to fix

Upgrade to a fixed version: python-pillow Pillow 13.0.0; Pypi Pillow 13.0.0. Check the vendor advisory for mitigations.

References

• https://github.com/python-pillow/Pillow/commit/68a3fe957d8a4d552e8c69d96066d749f0614c7e
• https://github.com/python-pillow/Pillow/releases/tag/13.0.0
• https://github.com/python-pillow/Pillow/security/advisories/GHSA-74r2-7ff9-mjj2

Get alerted when CVE-2026-112401 or the next vulnerability affects your stack