CVE-2026-84309

Name	CVE-2026-84309
Description	pypdf is a free and open-source pure-python PDF library. Prior to 6.16.0, an attacker can craft a PDF whose cyclic tree structure causes pypdf/generic/_data_structures.py TreeObject.insert_child to follow /Next links indefinitely when a writing code path inserts a child, producing an infinite loop. This issue is fixed in version 6.16.0.
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)

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
	trixie	5.4.0-1	vulnerable
	forky, sid	6.9.2-2	vulnerable
pypdf2 (PTS)	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)
pypdf2	source	(unstable)	(unfixed)

Notes

https://github.com/py-pdf/pypdf/security/advisories/GHSA-jp53-mhqp-8xcg
https://github.com/py-pdf/pypdf/pull/3964
Fixed by: https://github.com/py-pdf/pypdf/commit/c9ba557d565d57c53a0b3a0be06c0a4c29b0559b (6.16.0)