CVE-2026-1801

Name	CVE-2026-1801
Description	A flaw was found in libsoup, an HTTP client/server library. This HTTP Request Smuggling vulnerability arises from non-RFC-compliant parsing in the soup_filter_input_stream_read_line() logic, where libsoup accepts malformed chunk headers, such as lone line feed (LF) characters instead of the required carriage return and line feed (CRLF). A remote attacker can exploit this without authentication or user interaction by sending specially crafted chunked requests. This allows libsoup to parse and process multiple HTTP requests from a single network message, potentially leading to information disclosure.
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
libsoup2.4 (PTS)	bullseye	2.72.0-2	vulnerable
	bullseye (security)	2.72.0-2+deb11u3	vulnerable
	bookworm	2.74.3-1+deb12u1	vulnerable
	trixie	2.74.3-10.1	vulnerable
libsoup3 (PTS)	bookworm	3.2.3-0+deb12u2	vulnerable
	trixie	3.6.5-3	vulnerable
	forky	3.6.5-7	vulnerable
	sid	3.6.5-9	fixed

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)
libsoup3	source	(unstable)	3.6.5-8

Notes

https://gitlab.gnome.org/GNOME/libsoup/-/issues/481
https://gitlab.gnome.org/GNOME/libsoup/-/merge_requests/506
Fixed by: https://gitlab.gnome.org/GNOME/libsoup/-/commit/b9a1c0663ff8ab6e79715db4b35b54f560416ddd