CVE-2026-0966 Libssh: libssh: denial of service via zero-length input in ssh_get_hexa()
Remote attackers can cause a denial of service in libssh during GSSAPI authentication if high logging verbosity is enabled.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-0966?
CVE-2026-0966 is a medium-severity denial of service vulnerability in Redhat Enterprise Linux, published on 26 Mar 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official 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.
Weakness: CWE-124
Which versions are affected by CVE-2026-0966?
It affects 4 products.
Products include Libssh Libssh, Redhat Enterprise Linux, Redhat Hardened Images, Redhat Openshift Container Platform.
How do I fix CVE-2026-0966?
Apply the vendor's patch.
Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.
Is CVE-2026-0966 being exploited?
There is no known exploitation of CVE-2026-0966 in the wild and no public exploit code.
Other vulnerabilities in Redhat Enterprise Linux
- CVE-2026-59851 Libssh: libssh: authentication bypass via missing gssapi principal check
- CVE-2025-5987 Libssh: invalid return code for chacha20 poly1305 with openssl backend
- CVE-2025-14821 Libssh: libssh: insecure default configuration leads to local man-in-the-middle attacks on windows
- CVE-2012-4560 Memory corruption in n/a
- CVE-2012-4562 Integer overflow in n/a
Sources
Also known as AZL-81095, BELL-CVE-2026-0966, CLSA-2026-1777939234, CLSA-2026-1777939266, CLSA-2026-1778003186, CLSA-2026-1778003336 and 10 more.