What’s Vulnerable › Vulnerabilities

CVE-2026-55380: Pillow GdImageFile decompression bomb protection bypass

• 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: 2026-07-06 · updated 2026-10-25
• Weakness: CWE-789

Description

Pillow is a Python imaging library. Prior to 12.3.0, PIL/GdImageFile.py GdImageFile._open() read image dimensions from the GD 2.x header and stored them in self._size without calling Image._decompression_bomb_check(), allowing a crafted .gd file to trigger excessive C-heap allocation when loaded. This issue is fixed in version 12.3.0.

Affected products

• python-pillow Pillow: before 12.3.0 — fixed in 12.3.0
• Pypi Pillow: before 12.3.0; 1.0, 1.1, 1.2, 1.3, 1.4, 1.5 (+100) — fixed in 12.3.0

How to fix

Upgrade to a fixed version: python-pillow Pillow 12.3.0; Pypi Pillow 12.3.0. Check the vendor advisory for mitigations.

References

• https://github.com/python-pillow/Pillow/blob/main/docs/releasenotes/12.3.0.rst
• https://github.com/python-pillow/Pillow/commit/f39b0ae6624eb2d7c5c5d651d9bb5fdbd96a8675
• https://github.com/python-pillow/Pillow/security/advisories/GHSA-phj9-mv4w-65pm
• https://github.com/python-pillow/Pillow/security/advisories/GHSA-phj9-mv4w-65pm

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