CVE-2026-113793

pypdf: Possible infinite loop when removing tree items

State: Published
Severity: 6.0 Medium
Published: Oct 21, 2026
Updated: Oct 28, 2026
Reserved: Oct 20, 2026

Description

pypdf is a free and open-source pure-python PDF library. Prior to 6.20.1, removing an object from a crafted cyclic PDF tree, such as an outline item, can enter an infinite loop and block the current process. This issue is fixed in version 6.20.1.

Scores

CVSS	Score	Vector	Source
4.0	6.0 Medium	CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:P/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N	GitHub_M

Weaknesses

CWE-835 Loop with Unreachable Exit Condition ('Infinite Loop')

Affected Products

Product	Versions
pypdfpy-pdf	< 6.20.1Affected

References

https://github.com/py-pdf/pypdf/security/advisories/GHSA-9mx8-4j7g-633p
https://github.com/py-pdf/pypdf/pull/4188
https://github.com/py-pdf/pypdf/commit/c9c35b4471c2eb5fe078094f6c816e69d4ed25a0
https://github.com/py-pdf/pypdf/releases/tag/6.20.1

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