CVE-2026-55654

Name	CVE-2026-55654
Description	A flaw was found in OpenSSH. This vulnerability, a heap out-of-bounds read, occurs during the cleanup of GSSAPI (Generic Security Service Application Programming Interface) indicators when a trailing NULL termination is missing in the auth-indicators array. A remote attacker, under specific configurations involving GSSAPI authentication and a Kerberos environment, could exploit this to cause the SSH authentication path to crash or abort. This leads to a denial of service (DoS), impacting the availability of the SSH service.
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)
Debian Bugs	1143924

Vulnerable and fixed packages

The table below lists information on source packages.

Source Package	Release	Version	Status
openssh (PTS)	bookworm	1:9.2p1-2+deb12u10	vulnerable
	bookworm (security)	1:9.2p1-2+deb12u9	vulnerable
	trixie	1:10.0p1-7+deb13u4	vulnerable
	trixie (security)	1:10.0p1-7+deb13u2	vulnerable
	forky	1:10.4p1-5	fixed
	sid	1:10.5p1-1	fixed
openssh-gssapi (PTS)	forky	1:10.4p1-5	vulnerable
	sid	1:10.5p1-1	vulnerable

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

Package	Type	Release	Fixed Version	Urgency	Origin	Debian Bugs
openssh	source	(unstable)	1:10.4p1-5
openssh-gssapi	source	(unstable)	(unfixed)			1143924

Notes

[trixie] - openssh <no-dsa> (Minor issue)
[bookworm] - openssh <postponed> (Minor issue)
https://bugzilla.redhat.com/show_bug.cgi?id=2462493
openssh/1:10.4p1-5 dropped the GSS-API authentication and key exchange support