CVE-2026-22691

Name	CVE-2026-22691
Description	pypdf is a free and open-source pure-python PDF library. Prior to version 6.6.0, pypdf has possible long runtimes for malformed startxref. An attacker who uses this vulnerability can craft a PDF which leads to possibly long runtimes for invalid startxref entries. When rebuilding the cross-reference table, PDF files with lots of whitespace characters become problematic. Only the non-strict reading mode is affected. Only the non-strict reading mode is affected. This issue has been patched in version 6.6.0.
Source	CVE (at NVD; CERT, ENISA, LWN, oss-sec, fulldisc, Debian ELTS, Red Hat, Ubuntu, Gentoo, SUSE bugzilla/CVE, GitHub advisories/code/issues, web search, more)
Debian Bugs	1125187

Vulnerable and fixed packages

The table below lists information on source packages.

Source Package	Release	Version	Status
pypdf (PTS)	bookworm	3.4.1-1+deb12u1	vulnerable
	forky, sid, trixie	5.4.0-1	vulnerable
pypdf2 (PTS)	bullseye	1.26.0-4+deb11u1	vulnerable
	bookworm	2.12.1-3+deb12u1	vulnerable

The information below is based on the following data on fixed versions.

Package	Type	Release	Fixed Version	Urgency	Origin	Debian Bugs
pypdf	source	(unstable)	(unfixed)			1125187
pypdf2	source	(unstable)	(unfixed)

Notes

https://github.com/py-pdf/pypdf/security/advisories/GHSA-4f6g-68pf-7vhv
https://github.com/py-pdf/pypdf/pull/3594
Fixed by: https://github.com/py-pdf/pypdf/commit/294165726b646bb7799be1cc787f593f2fdbcf45 (6.6.0)