ubuntu-cve-2026-0966
Vulnerability from osv_ubuntu
Published
2026-02-13 00:00
Modified
2026-05-14 11:38
Summary
Details

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.

Severity
6.5 (Medium)
CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:H
8.2 (High)
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:H
N/A (UNKNOWN)
low
References
To clipboard 

{
  "affected": [
    {
      "ecosystem_specific": {
        "availability": "Available with Ubuntu Pro (Infra-only): https://ubuntu.com/pro",
        "binaries": [
          {
            "binary_name": "libssh-4",
            "binary_version": "0.6.3-4.3ubuntu0.6+esm4"
          },
          {
            "binary_name": "libssh-gcrypt-4",
            "binary_version": "0.6.3-4.3ubuntu0.6+esm4"
          }
        ],
        "priority_reason": "Low severity DoS issue"
      },
      "package": {
        "ecosystem": "Ubuntu:Pro:16.04:LTS",
        "name": "libssh",
        "purl": "pkg:deb/ubuntu/libssh@0.6.3-4.3ubuntu0.6+esm4?arch=source\u0026distro=esm-infra/xenial"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "0.6.3-4.3ubuntu0.6+esm4"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "0.6.3-3ubuntu3",
        "0.6.3-4.1",
        "0.6.3-4.2",
        "0.6.3-4.2ubuntu1",
        "0.6.3-4.3",
        "0.6.3-4.3ubuntu0.1",
        "0.6.3-4.3ubuntu0.2",
        "0.6.3-4.3ubuntu0.5",
        "0.6.3-4.3ubuntu0.6",
        "0.6.3-4.3ubuntu0.6+esm1",
        "0.6.3-4.3ubuntu0.6+esm2",
        "0.6.3-4.3ubuntu0.6+esm3"
      ]
    },
    {
      "ecosystem_specific": {
        "availability": "Available with Ubuntu Pro (Infra-only): https://ubuntu.com/pro",
        "binaries": [
          {
            "binary_name": "libssh-4",
            "binary_version": "0.8.0~20170825.94fa1e38-1ubuntu0.7+esm6"
          },
          {
            "binary_name": "libssh-gcrypt-4",
            "binary_version": "0.8.0~20170825.94fa1e38-1ubuntu0.7+esm6"
          }
        ],
        "priority_reason": "Low severity DoS issue"
      },
      "package": {
        "ecosystem": "Ubuntu:Pro:18.04:LTS",
        "name": "libssh",
        "purl": "pkg:deb/ubuntu/libssh@0.8.0~20170825.94fa1e38-1ubuntu0.7+esm6?arch=source\u0026distro=esm-infra/bionic"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "0.8.0~20170825.94fa1e38-1ubuntu0.7+esm6"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "0.7.5-1",
        "0.8.0~20170825.94fa1e38-1",
        "0.8.0~20170825.94fa1e38-1build1",
        "0.8.0~20170825.94fa1e38-1ubuntu0.1",
        "0.8.0~20170825.94fa1e38-1ubuntu0.2",
        "0.8.0~20170825.94fa1e38-1ubuntu0.5",
        "0.8.0~20170825.94fa1e38-1ubuntu0.6",
        "0.8.0~20170825.94fa1e38-1ubuntu0.7",
        "0.8.0~20170825.94fa1e38-1ubuntu0.7+esm3",
        "0.8.0~20170825.94fa1e38-1ubuntu0.7+esm4",
        "0.8.0~20170825.94fa1e38-1ubuntu0.7+esm5"
      ]
    },
    {
      "ecosystem_specific": {
        "availability": "Available with Ubuntu Pro (Infra-only): https://ubuntu.com/pro",
        "binaries": [
          {
            "binary_name": "libssh-4",
            "binary_version": "0.9.3-2ubuntu2.5+esm3"
          },
          {
            "binary_name": "libssh-gcrypt-4",
            "binary_version": "0.9.3-2ubuntu2.5+esm3"
          }
        ],
        "priority_reason": "Low severity DoS issue"
      },
      "package": {
        "ecosystem": "Ubuntu:Pro:20.04:LTS",
        "name": "libssh",
        "purl": "pkg:deb/ubuntu/libssh@0.9.3-2ubuntu2.5+esm3?arch=source\u0026distro=esm-infra/focal"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "0.9.3-2ubuntu2.5+esm3"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "0.9.0-1ubuntu1",
        "0.9.0-1ubuntu4",
        "0.9.0-1ubuntu5",
        "0.9.3-2ubuntu1",
        "0.9.3-2ubuntu2",
        "0.9.3-2ubuntu2.1",
        "0.9.3-2ubuntu2.2",
        "0.9.3-2ubuntu2.3",
        "0.9.3-2ubuntu2.4",
        "0.9.3-2ubuntu2.5",
        "0.9.3-2ubuntu2.5+esm1",
        "0.9.3-2ubuntu2.5+esm2"
      ]
    },
    {
      "ecosystem_specific": {
        "availability": "No subscription required",
        "binaries": [
          {
            "binary_name": "libssh-4",
            "binary_version": "0.9.6-2ubuntu0.22.04.6"
          },
          {
            "binary_name": "libssh-gcrypt-4",
            "binary_version": "0.9.6-2ubuntu0.22.04.6"
          }
        ],
        "priority_reason": "Low severity DoS issue"
      },
      "package": {
        "ecosystem": "Ubuntu:22.04:LTS",
        "name": "libssh",
        "purl": "pkg:deb/ubuntu/libssh@0.9.6-2ubuntu0.22.04.6?arch=source\u0026distro=jammy"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "0.9.6-2ubuntu0.22.04.6"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "0.9.6-1",
        "0.9.6-1build1",
        "0.9.6-2",
        "0.9.6-2build1",
        "0.9.6-2ubuntu0.22.04.1",
        "0.9.6-2ubuntu0.22.04.2",
        "0.9.6-2ubuntu0.22.04.3",
        "0.9.6-2ubuntu0.22.04.4",
        "0.9.6-2ubuntu0.22.04.5"
      ]
    },
    {
      "ecosystem_specific": {
        "availability": "No subscription required",
        "binaries": [
          {
            "binary_name": "libssh-4",
            "binary_version": "0.10.6-2ubuntu0.3"
          },
          {
            "binary_name": "libssh-gcrypt-4",
            "binary_version": "0.10.6-2ubuntu0.3"
          }
        ],
        "priority_reason": "Low severity DoS issue"
      },
      "package": {
        "ecosystem": "Ubuntu:24.04:LTS",
        "name": "libssh",
        "purl": "pkg:deb/ubuntu/libssh@0.10.6-2ubuntu0.3?arch=source\u0026distro=noble"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "0.10.6-2ubuntu0.3"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "0.10.5-3ubuntu1",
        "0.10.5-3ubuntu2",
        "0.10.6-2",
        "0.10.6-2build1",
        "0.10.6-2build2",
        "0.10.6-2ubuntu0.1",
        "0.10.6-2ubuntu0.2"
      ]
    },
    {
      "ecosystem_specific": {
        "availability": "No subscription required",
        "binaries": [
          {
            "binary_name": "libssh-4",
            "binary_version": "0.11.2-1ubuntu0.2"
          }
        ],
        "priority_reason": "Low severity DoS issue"
      },
      "package": {
        "ecosystem": "Ubuntu:25.10",
        "name": "libssh",
        "purl": "pkg:deb/ubuntu/libssh@0.11.2-1ubuntu0.2?arch=source\u0026distro=questing"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "0.11.2-1ubuntu0.2"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "0.11.1-1",
        "0.11.1-2",
        "0.11.2-1",
        "0.11.2-1build1",
        "0.11.2-1ubuntu0.1"
      ]
    }
  ],
  "aliases": [],
  "details": "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\u0027s 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.",
  "id": "UBUNTU-CVE-2026-0966",
  "modified": "2026-05-14T11:38:25Z",
  "published": "2026-02-13T00:00:00Z",
  "references": [
    {
      "type": "REPORT",
      "url": "https://ubuntu.com/security/CVE-2026-0966"
    },
    {
      "type": "REPORT",
      "url": "https://www.cve.org/CVERecord?id=CVE-2026-0966"
    },
    {
      "type": "REPORT",
      "url": "https://www.libssh.org/security/advisories/CVE-2026-0966.txt"
    },
    {
      "type": "ADVISORY",
      "url": "https://ubuntu.com/security/notices/USN-8051-1"
    },
    {
      "type": "ADVISORY",
      "url": "https://ubuntu.com/security/notices/USN-8051-2"
    }
  ],
  "related": [
    "USN-8051-1",
    "USN-8051-2"
  ],
  "schema_version": "1.7.0",
  "severity": [
    {
      "score": "CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:H",
      "type": "CVSS_V3"
    },
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:H",
      "type": "CVSS_V3"
    },
    {
      "score": "low",
      "type": "Ubuntu"
    }
  ],
  "upstream": [
    "CVE-2026-0966"
  ]
}



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Sightings

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Nomenclature

  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
  • Confirmed: The vulnerability has been validated from an analyst's perspective.
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  • Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
  • Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
  • Not confirmed: The user expressed doubt about the validity of the vulnerability.
  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.


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