CVE-2026-66337

Name	CVE-2026-66337
Description	A flaw was found in libsoup. An unsigned integer underflow in the soup_filter_input_stream_read_until() function causes a heap buffer over-read when parsing multipart HTTP responses. A malicious HTTP server can exploit this by sending a crafted multipart response, potentially causing the client application to crash or disclose sensitive heap memory.
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, sid	3.6.6-1	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)
libsoup3	source	(unstable)	(unfixed)

https://bugzilla.redhat.com/show_bug.cgi?id=2506949
https://gitlab.gnome.org/GNOME/libsoup/-/work_items/532