CVE-2026-113794

pypdf: Possible infinite loop when hitting EOF in standard xref table

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 6.20.0, an attacker can craft an incomplete PDF that ends inside a standard cross-reference table, causing pypdf to mishandle the unexpected end of file and enter an infinite loop. This issue is fixed in version 6.20.0.

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	< 6.20.0Affected

References

https://github.com/py-pdf/pypdf/security/advisories/GHSA-39mj-jf6j-2qj3
https://github.com/py-pdf/pypdf/issues/4169
https://github.com/py-pdf/pypdf/pull/4170
https://github.com/py-pdf/pypdf/commit/37e1cd681744bac38b159f7e1c614eee8d639c58
https://github.com/py-pdf/pypdf/releases/tag/6.20.0

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