CVE-2025-8277

Name	CVE-2025-8277
Description	A flaw was found in libssh's handling of key exchange (KEX) processes when a client repeatedly sends incorrect KEX guesses. The library fails to free memory during these rekey operations, which can gradually exhaust system memory. This issue can lead to crashes on the client side, particularly when using libgcrypt, which impacts application stability and availability.
Source	CVE (at NVD; CERT, LWN, oss-sec, fulldisc, 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
libssh (PTS)	bullseye (security), bullseye	0.9.8-0+deb11u1	vulnerable
	bookworm, bookworm (security)	0.10.6-0+deb12u1	vulnerable
	forky, sid, trixie	0.11.2-1	vulnerable

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

Package	Type	Release	Fixed Version	Urgency	Origin	Debian Bugs
libssh	source	(unstable)	(unfixed)

Notes

[trixie] - libssh <no-dsa> (Minor issue)
[bookworm] - libssh <no-dsa> (Minor issue)
https://bugzilla.redhat.com/show_bug.cgi?id=2383888
https://www.libssh.org/security/advisories/CVE-2025-8277.txt