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.
History

Mon, 11 May 2026 16:30:00 +0000

Type Values Removed Values Added
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. 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.
Title Libssh: buffer underflow in ssh_get_hexa() on invalid input Libssh: libssh: denial of service via zero-length input in ssh_get_hexa()
Metrics cvssV3_0

{'score': 6.5, 'vector': 'CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:L'}

cvssV3_0

{'score': 6.5, 'vector': 'CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:H'}


Thu, 30 Apr 2026 16:30:00 +0000

Type Values Removed Values Added
First Time appeared Redhat hardened Images
Redhat openshift Container Platform
CPEs cpe:2.3:a:libssh:libssh:*:*:*:*:*:*:*:*
cpe:2.3:a:redhat:hardened_images:-:*:*:*:*:*:*:*
cpe:2.3:a:redhat:openshift_container_platform:4.0:*:*:*:*:*:*:*
cpe:2.3:o:redhat:enterprise_linux:10.0:*:*:*:*:*:*:*
cpe:2.3:o:redhat:enterprise_linux:8.0:*:*:*:*:*:*:*
cpe:2.3:o:redhat:enterprise_linux:9.0:*:*:*:*:*:*:*
Vendors & Products Redhat hardened Images
Redhat openshift Container Platform
Metrics cvssV3_1

{'score': 8.2, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:H'}


Fri, 24 Apr 2026 23:00:00 +0000

Type Values Removed Values Added
References

Thu, 09 Apr 2026 18:15:00 +0000

Type Values Removed Values Added
First Time appeared Redhat hummingbird
CPEs cpe:/a:redhat:hummingbird:1
Vendors & Products Redhat hummingbird

Fri, 27 Mar 2026 20:15:00 +0000

Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'yes', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}


Thu, 26 Mar 2026 21:30:00 +0000


Thu, 26 Mar 2026 20:30:00 +0000

Type Values Removed Values Added
Description No description is available for this CVE. 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.
Title libssh: Buffer underflow in ssh_get_hexa() on invalid input Libssh: buffer underflow in ssh_get_hexa() on invalid input
First Time appeared Redhat
Redhat enterprise Linux
Redhat openshift
Weaknesses CWE-124
CPEs cpe:/a:redhat:openshift:4
cpe:/o:redhat:enterprise_linux:10
cpe:/o:redhat:enterprise_linux:6
cpe:/o:redhat:enterprise_linux:7
cpe:/o:redhat:enterprise_linux:8
cpe:/o:redhat:enterprise_linux:9
Vendors & Products Redhat
Redhat enterprise Linux
Redhat openshift
References
Metrics cvssV3_0

{'score': 6.5, 'vector': 'CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:L'}


Mon, 16 Feb 2026 12:15:00 +0000

Type Values Removed Values Added
First Time appeared Libssh
Libssh libssh
Vendors & Products Libssh
Libssh libssh

Wed, 11 Feb 2026 00:15:00 +0000

Type Values Removed Values Added
Description No description is available for this CVE.
Title libssh: Buffer underflow in ssh_get_hexa() on invalid input
References
Metrics threat_severity

None

threat_severity

Moderate


cve-icon MITRE

Status: PUBLISHED

Assigner: redhat

Published:

Updated: 2026-05-11T16:13:21.843Z

Reserved: 2026-01-14T21:54:59.132Z

Link: CVE-2026-0966

cve-icon Vulnrichment

Updated: 2026-03-27T19:52:27.669Z

cve-icon NVD

Status : Modified

Published: 2026-03-26T21:17:00.783

Modified: 2026-05-11T17:16:11.670

Link: CVE-2026-0966

cve-icon Redhat

Severity : Moderate

Publid Date: 2026-02-10T18:47:15Z

Links: CVE-2026-0966 - Bugzilla

cve-icon OpenCVE Enrichment

Updated: 2026-05-11T18:00:14Z