What’s Vulnerable › Vulnerabilities

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

• Severity: medium (CVSS 6.5 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.4% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-10-21 · updated 2026-10-27
• Weakness: CWE-407

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 products

• python-pillow Pillow: from 11.0.0 before 13.0.0 — fixed in 13.0.0
• python-pillow Pillow: from 11.0.0, < 13.0.0

How to fix

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

References

• https://github.com/python-pillow/Pillow/commit/806e38381c781f32bbd22f4cd026678acd40fd6c
• https://github.com/python-pillow/Pillow/pull/10073
• https://github.com/python-pillow/Pillow/releases/tag/13.0.0
• https://github.com/python-pillow/Pillow/security/advisories/GHSA-g4qv-2jxx-769h

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