Bug#1143924: openssh: CVE-2026-55654

Source: openssh
X-Debbugs-CC: [email protected]
Severity: important
Tags: security

Hi,

The following vulnerability was published for openssh.

CVE-2026-55654[0]:
| 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.

This is an issue in the gssapi patch set, for which Red Hat shipped
an update: https://bugzilla.redhat.com/show_bug.cgi?id=2462493

TTBOMK Red Hat is the canonical upstream for the openssh/gssapi
patches and with Debian also shipping support we're probably
also affected?


If you fix the vulnerability please also make sure to include the
CVE (Common Vulnerabilities & Exposures) id in your changelog entry.

For further information see:

[0] https://security-tracker.debian.org/tracker/CVE-2026-55654
    https://www.cve.org/CVERecord?id=CVE-2026-55654

Please adjust the affected versions in the BTS as needed.