CVE-2026-0966

Name	CVE-2026-0966
Description	The API function `ssh_get_hexa()` is vulnerable, when 0-lenght input is provided to this function. This function is used internally in `ssh_get_fingerprint_hash()` and `ssh_print_hexa()` (deprecated), which is vulnerable to the same input (length is provided by the calling application). The function is also used internally in the gssapi code for logging the OIDs received by the server during GSSAPI authentication. This could be triggered remotely, when the server allows GSSAPI authentication and logging verbosity is set at least to SSH_LOG_PACKET (3). This could cause self-DoS of the per-connection daemon process.
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	1127693

Vulnerable and fixed packages

The table below lists information on source packages.

Source Package	Release	Version	Status
libssh (PTS)	bullseye	0.9.8-0+deb11u1	vulnerable
	bullseye (security)	0.9.8-0+deb11u2	vulnerable
	bookworm	0.10.6-0+deb12u2	vulnerable
	bookworm (security)	0.10.6-0+deb12u1	vulnerable
	trixie	0.11.2-1+deb13u1	vulnerable
	forky, sid	0.12.0-3	fixed

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

Package	Type	Release	Fixed Version	Urgency	Origin	Debian Bugs
libssh	source	(unstable)	0.12.0-1			1127693

Notes

[trixie] - libssh <no-dsa> (Minor issue)
[bookworm] - libssh <no-dsa> (Minor issue)
[bullseye] - libssh <postponed> (Minor issue)
https://www.libssh.org/security/advisories/CVE-2026-0966.txt
Documentation: https://git.libssh.org/projects/libssh.git/commit/?id=3e1d276a5a030938a8f144f46ff4f2a2efe31ced (libssh-0.11.4)
Tests: https://git.libssh.org/projects/libssh.git/commit/?id=b156391833c66322436cf177d57e10b0325fbcc8 (libssh-0.11.4)
Fixed by: https://git.libssh.org/projects/libssh.git/commit/?id=6ba5ff1b7b1547a59f750fbc06b89737b7456117 (libssh-0.11.4)