CVE-2025-9901

Name	CVE-2025-9901
Description	A flaw was found in libsoup’s caching mechanism, SoupCache, where the HTTP Vary header is ignored when evaluating cached responses. This header ensures that responses vary appropriately based on request headers such as language or authentication. Without this check, cached content can be incorrectly reused across different requests, potentially exposing sensitive user information. While the issue is unlikely to affect everyday desktop use, it could result in confidentiality breaches in proxy or multi-user environments.
Source	CVE (at NVD; CERT, LWN, oss-sec, fulldisc, Debian ELTS, Red Hat, Ubuntu, Gentoo, SUSE bugzilla/CVE, GitHub advisories/code/issues, web search, more)
Debian Bugs	1113991, 1113992

Vulnerable and fixed packages

The table below lists information on source packages.

Source Package	Release	Version	Status
libsoup2.4 (PTS)	bullseye	2.72.0-2	vulnerable
	bullseye (security)	2.72.0-2+deb11u2	vulnerable
	bookworm	2.74.3-1+deb12u1	vulnerable
	sid, trixie	2.74.3-10.1	vulnerable
libsoup3 (PTS)	bookworm	3.2.3-0+deb12u2	vulnerable
	trixie	3.6.5-3	vulnerable
	forky, sid	3.6.5-4	vulnerable

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

Package	Type	Release	Fixed Version	Urgency	Origin	Debian Bugs
libsoup2.4	source	(unstable)	(unfixed)			1113992
libsoup3	source	(unstable)	(unfixed)			1113991

Notes

[trixie] - libsoup3 <no-dsa> (Minor issue)
[bookworm] - libsoup3 <no-dsa> (Minor issue)
[trixie] - libsoup2.4 <no-dsa> (Minor issue)
[bookworm] - libsoup2.4 <no-dsa> (Minor issue)
https://gitlab.gnome.org/GNOME/libsoup/-/issues/453