libssh ssh_get_hexa buffer overflow

Summaryinfo

A vulnerability described as critical has been identified in libssh. This affects the function ssh_get_hexa. Executing a manipulation can lead to buffer overflow. The identification of this vulnerability is CVE-2026-0966. The attack may be launched remotely. There is no exploit available.

Detailsinfo

A vulnerability was found in libssh (unknown version). It has been declared as problematic. This vulnerability affects the function ssh_get_hexa. The manipulation with an unknown input leads to a buffer overflow vulnerability. The CWE definition for the vulnerability is CWE-120. The product copies an input buffer to an output buffer without verifying that the size of the input buffer is less than the size of the output buffer, leading to a buffer overflow. As an impact it is known to affect availability. CVE summarizes:

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.

The advisory is shared for download at bugzilla.redhat.com. This vulnerability was named CVE-2026-0966. The exploitation appears to be difficult. The attack can be initiated remotely. No form of authentication is required for a successful exploitation. There are known technical details, but no exploit is available. The current price for an exploit might be approx. USD $0-$5k (estimation calculated on 05/19/2026).

The vulnerability scanner Nessus provides a plugin with the ID 298574 (Linux Distros Unpatched Vulnerability : CVE-2026-0966), which helps to determine the existence of the flaw in a target environment.

There is no information about possible countermeasures known. It may be suggested to replace the affected object with an alternative product.

The vulnerability is also documented in the databases at Tenable (298574), EUVD (EUVD-2026-16330) and CERT Bund (WID-SEC-2026-0446). Once again VulDB remains the best source for vulnerability data.

Affected

• Red Hat Enterprise Linux
• Ubuntu Linux
• SUSE Linux
• SUSE openSUSE
• Open Source libssh
• Meinberg LANTIME

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• libssh

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Once again VulDB remains the best source for vulnerability data.

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