What’s Vulnerable › Vulnerabilities

CVE-2026-112406: Pillow: Infinite loop in PdfParser.rewrite_pages on page tree Parent cycle

• Severity: high (CVSS 7.5 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: yes
• Published: 2026-10-19 · updated 2026-10-27
• Weakness: CWE-835

Description

Pillow is a Python imaging library. From 5.1.0 until 13.0.0, Pillow can enter an infinite loop while rewriting PDF pages. PdfParser.rewrite_pages() follows Parent relationships without detecting a cycle in the page tree. An attacker can supply a cyclic PDF to an application that appends an image to that PDF. This can hold the worker at full CPU and deny service. This issue is fixed in version 13.0.0.

Affected products

• python-pillow Pillow: from 5.1.0 before 13.0.0 — fixed in 13.0.0
• Pypi Pillow: from 5.1.0 before 13.0.0; 10.0.0, 10.0.1, 10.1.0, 10.2.0, 10.3.0, 10.4.0 (+43) — fixed in 13.0.0
• python-pillow Pillow: from 5.1.0, < 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/b3ebf20c694f2f12537a629c30229a1d5a53f777
• https://github.com/python-pillow/Pillow/releases/tag/13.0.0
• https://github.com/python-pillow/Pillow/security/advisories/GHSA-f2g6-542v-9j58

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