CVE-2026-115580

pypdf: Possible long runtimes for large xref table header limits

State: Published
Severity: 7.1 High
Published: Oct 23, 2026
Updated: Oct 29, 2026
Reserved: Oct 22, 2026

Description

pypdf is a free and open-source pure-python PDF library. Prior to 6.21.2, an attacker can craft a PDF with a standard cross-reference table whose declared entry count exceeds what the file can contain, causing excessive processing and long runtimes when the file is opened. This issue is fixed in version 6.21.2.

Scores

CVSS	Score	Vector	Source
4.0	7.1 High	CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N	GitHub_M

Weaknesses

CWE-834 Excessive Iteration

Affected Products

Product	Versions
pypdfpy-pdf	< 6.21.2Affected

References

https://github.com/py-pdf/pypdf/security/advisories/GHSA-gmh7-3g9r-mjh5
https://github.com/py-pdf/pypdf/pull/4239
https://github.com/py-pdf/pypdf/commit/a3061e34b169d34478d520f5f049c53cfb1482b2
https://github.com/py-pdf/pypdf/releases/tag/6.21.2

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