CVE-2026-102997

Name	CVE-2026-102997
Description	pypdf is a free and open-source pure-python PDF library. Prior to 6.18.1, a crafted PDF containing a partially malformed /FlateDecode stream with padded data can force pypdf/filters.py to use inefficient byte-by-byte decompression while the earlier recovery counter fails to advance for bytes that successfully decode, causing long runtimes and application unavailability. This is a residual issue after the malformed FlateDecode recovery fix. This issue is fixed in version 6.18.1.
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	6.9.2-2	vulnerable
	sid	6.19.0-1	fixed
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)	6.19.0-1
pypdf2	source	(unstable)	(unfixed)

Notes

https://github.com/py-pdf/pypdf/security/advisories/GHSA-jw7q-gvrg-4vj3
https://github.com/py-pdf/pypdf/pull/4073
Fixed by: https://github.com/py-pdf/pypdf/commit/d9d38cf99b115deb562d3b68f36c33027bc04f79 (6.18.1)