CVE-2026-59937

pypdf: Possible long runtimes for repeated malformed cross-reference entries

State: Published
Severity: 6.9 Medium
Published: Jul 8, 2026
Updated: Jul 9, 2026
Reserved: Jul 7, 2026

Description

pypdf is a free and open-source pure-python PDF library. Prior to 6.14.0, an attacker can craft a PDF with repeated malformed cross-reference streams that cause pypdf to spend long runtimes recovering broken cross-reference table entries. This issue is fixed in version 6.14.0.

Scores

CVSS	Score	Vector	Source
4.0	6.9 Medium	CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N	GitHub_M

Weaknesses

CWE-400 Uncontrolled Resource Consumption

Affected Products

Product	Versions
pypdfpy-pdf	< 6.14.0Affected

References

https://github.com/py-pdf/pypdf/security/advisories/GHSA-55h5-xmcq-c37v
https://github.com/py-pdf/pypdf/pull/3887
https://github.com/py-pdf/pypdf/commit/b5fc5aa714f4b696fb9b1deaa35a9e4a4eb50dae
https://github.com/py-pdf/pypdf/releases/tag/6.14.0

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