Description
A flaw was found in libssh. The API function `ssh_get_hexa()` is vulnerable to a denial of service when processing zero-length input. This can be exploited remotely by an attacker during GSSAPI (Generic Security Service Application Program Interface) authentication if the server's logging verbosity is set to `SSH_LOG_PACKET (3)` or higher. Successful exploitation could lead to a self-Denial of Service of the per-connection daemon process.
Problem types
Buffer Underwrite ('Buffer Underflow')
Product status
0:0.12.0-2.el10 (rpm) before *
0:0.10.4-18.el9 (rpm) before *
0:0.10.4-18.el9 (rpm) before *
0.12.0-1.1.hum1 (rpm) before *
Timeline
| 2026-01-26: | Reported to Red Hat. |
| 2026-02-10: | Made public. |
Credits
Red Hat would like to thank Jakub Jelen (libssh), Jun Xu, Kang Yang, and Yunhang Zhang for reporting this issue.
References
access.redhat.com/errata/RHSA-2026:18160 (RHSA-2026:18160)
access.redhat.com/errata/RHSA-2026:18683 (RHSA-2026:18683)
access.redhat.com/errata/RHSA-2026:7067 (RHSA-2026:7067)
access.redhat.com/security/cve/CVE-2026-0966
bugzilla.redhat.com/show_bug.cgi?id=2433121 (RHBZ#2433121)
www.libssh.org/...ibssh-0-12-0-and-0-11-4-security-releases/