usn-6279-1
Vulnerability from osv_ubuntu
Published
2023-08-09 06:08
Modified
2026-06-29 10:53
Summary
openssh update
Details

It was discovered that OpenSSH has an observable discrepancy leading to an information leak in the algorithm negotiation. This update mitigates the issue by tweaking the client hostkey preference ordering algorithm to prefer the default ordering if the user has a key that matches the best-preference default algorithm.

References
To clipboard 

{
  "affected": [
    {
      "database_specific": {
        "cves_map": {
          "cves": [],
          "ecosystem": "Ubuntu:Pro:14.04:LTS"
        }
      },
      "ecosystem_specific": {
        "availability": "Available with Ubuntu Pro (Infra-only): https://ubuntu.com/pro",
        "binaries": [
          {
            "binary_name": "openssh-client",
            "binary_version": "1:6.6p1-2ubuntu2.13+esm2"
          },
          {
            "binary_name": "openssh-server",
            "binary_version": "1:6.6p1-2ubuntu2.13+esm2"
          },
          {
            "binary_name": "openssh-sftp-server",
            "binary_version": "1:6.6p1-2ubuntu2.13+esm2"
          },
          {
            "binary_name": "ssh",
            "binary_version": "1:6.6p1-2ubuntu2.13+esm2"
          },
          {
            "binary_name": "ssh-askpass-gnome",
            "binary_version": "1:6.6p1-2ubuntu2.13+esm2"
          },
          {
            "binary_name": "ssh-krb5",
            "binary_version": "1:6.6p1-2ubuntu2.13+esm2"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:Pro:14.04:LTS",
        "name": "openssh",
        "purl": "pkg:deb/ubuntu/openssh@1:6.6p1-2ubuntu2.13+esm2?arch=source\u0026distro=trusty/esm"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "1:6.6p1-2ubuntu2.13+esm2"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "1:6.2p2-6",
        "1:6.2p2-6ubuntu1",
        "1:6.4p1-1",
        "1:6.4p1-2",
        "1:6.5p1-1",
        "1:6.5p1-2",
        "1:6.5p1-3",
        "1:6.5p1-4",
        "1:6.5p1-6",
        "1:6.6p1-1",
        "1:6.6p1-2",
        "1:6.6p1-2ubuntu1",
        "1:6.6p1-2ubuntu2",
        "1:6.6p1-2ubuntu2.2",
        "1:6.6p1-2ubuntu2.3",
        "1:6.6p1-2ubuntu2.4",
        "1:6.6p1-2ubuntu2.6",
        "1:6.6p1-2ubuntu2.7",
        "1:6.6p1-2ubuntu2.8",
        "1:6.6p1-2ubuntu2.10",
        "1:6.6p1-2ubuntu2.11",
        "1:6.6p1-2ubuntu2.12",
        "1:6.6p1-2ubuntu2.13",
        "1:6.6p1-2ubuntu2.13+esm1"
      ]
    },
    {
      "database_specific": {
        "cves_map": {
          "cves": [],
          "ecosystem": "Ubuntu:Pro:16.04:LTS"
        }
      },
      "ecosystem_specific": {
        "availability": "Available with Ubuntu Pro (Infra-only): https://ubuntu.com/pro",
        "binaries": [
          {
            "binary_name": "openssh-client",
            "binary_version": "1:7.2p2-4ubuntu2.10+esm4"
          },
          {
            "binary_name": "openssh-client-ssh1",
            "binary_version": "1:7.2p2-4ubuntu2.10+esm4"
          },
          {
            "binary_name": "openssh-server",
            "binary_version": "1:7.2p2-4ubuntu2.10+esm4"
          },
          {
            "binary_name": "openssh-sftp-server",
            "binary_version": "1:7.2p2-4ubuntu2.10+esm4"
          },
          {
            "binary_name": "ssh",
            "binary_version": "1:7.2p2-4ubuntu2.10+esm4"
          },
          {
            "binary_name": "ssh-askpass-gnome",
            "binary_version": "1:7.2p2-4ubuntu2.10+esm4"
          },
          {
            "binary_name": "ssh-krb5",
            "binary_version": "1:7.2p2-4ubuntu2.10+esm4"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:Pro:16.04:LTS",
        "name": "openssh",
        "purl": "pkg:deb/ubuntu/openssh@1:7.2p2-4ubuntu2.10+esm4?arch=source\u0026distro=esm-infra/xenial"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "1:7.2p2-4ubuntu2.10+esm4"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "1:6.9p1-2",
        "1:6.9p1-3",
        "1:7.1p1-1",
        "1:7.1p1-3",
        "1:7.1p1-4",
        "1:7.1p1-6",
        "1:7.1p2-1",
        "1:7.1p2-2",
        "1:7.2p1-1",
        "1:7.2p2-1",
        "1:7.2p2-2",
        "1:7.2p2-3",
        "1:7.2p2-4",
        "1:7.2p2-4ubuntu1",
        "1:7.2p2-4ubuntu2.1",
        "1:7.2p2-4ubuntu2.2",
        "1:7.2p2-4ubuntu2.4",
        "1:7.2p2-4ubuntu2.5",
        "1:7.2p2-4ubuntu2.6",
        "1:7.2p2-4ubuntu2.7",
        "1:7.2p2-4ubuntu2.8",
        "1:7.2p2-4ubuntu2.10",
        "1:7.2p2-4ubuntu2.10+esm1",
        "1:7.2p2-4ubuntu2.10+esm2",
        "1:7.2p2-4ubuntu2.10+esm3"
      ]
    },
    {
      "database_specific": {
        "cves_map": {
          "cves": [],
          "ecosystem": "Ubuntu:Pro:18.04:LTS"
        }
      },
      "ecosystem_specific": {
        "availability": "Available with Ubuntu Pro (Infra-only): https://ubuntu.com/pro",
        "binaries": [
          {
            "binary_name": "openssh-client",
            "binary_version": "1:7.6p1-4ubuntu0.7+esm2"
          },
          {
            "binary_name": "openssh-server",
            "binary_version": "1:7.6p1-4ubuntu0.7+esm2"
          },
          {
            "binary_name": "openssh-sftp-server",
            "binary_version": "1:7.6p1-4ubuntu0.7+esm2"
          },
          {
            "binary_name": "ssh",
            "binary_version": "1:7.6p1-4ubuntu0.7+esm2"
          },
          {
            "binary_name": "ssh-askpass-gnome",
            "binary_version": "1:7.6p1-4ubuntu0.7+esm2"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:Pro:18.04:LTS",
        "name": "openssh",
        "purl": "pkg:deb/ubuntu/openssh@1:7.6p1-4ubuntu0.7+esm2?arch=source\u0026distro=esm-infra/bionic"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "1:7.6p1-4ubuntu0.7+esm2"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "1:7.5p1-10",
        "1:7.6p1-4",
        "1:7.6p1-4ubuntu0.1",
        "1:7.6p1-4ubuntu0.2",
        "1:7.6p1-4ubuntu0.3",
        "1:7.6p1-4ubuntu0.5",
        "1:7.6p1-4ubuntu0.6",
        "1:7.6p1-4ubuntu0.7",
        "1:7.6p1-4ubuntu0.7+esm1"
      ]
    },
    {
      "database_specific": {
        "cves_map": {
          "cves": [],
          "ecosystem": "Ubuntu:20.04:LTS"
        }
      },
      "ecosystem_specific": {
        "availability": "No subscription required",
        "binaries": [
          {
            "binary_name": "openssh-client",
            "binary_version": "1:8.2p1-4ubuntu0.9"
          },
          {
            "binary_name": "openssh-server",
            "binary_version": "1:8.2p1-4ubuntu0.9"
          },
          {
            "binary_name": "openssh-sftp-server",
            "binary_version": "1:8.2p1-4ubuntu0.9"
          },
          {
            "binary_name": "openssh-tests",
            "binary_version": "1:8.2p1-4ubuntu0.9"
          },
          {
            "binary_name": "ssh",
            "binary_version": "1:8.2p1-4ubuntu0.9"
          },
          {
            "binary_name": "ssh-askpass-gnome",
            "binary_version": "1:8.2p1-4ubuntu0.9"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:20.04:LTS",
        "name": "openssh",
        "purl": "pkg:deb/ubuntu/openssh@1:8.2p1-4ubuntu0.9?arch=source\u0026distro=focal"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "1:8.2p1-4ubuntu0.9"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "1:8.0p1-6build1",
        "1:8.1p1-1",
        "1:8.1p1-5",
        "1:8.2p1-4",
        "1:8.2p1-4ubuntu0.1",
        "1:8.2p1-4ubuntu0.2",
        "1:8.2p1-4ubuntu0.3",
        "1:8.2p1-4ubuntu0.4",
        "1:8.2p1-4ubuntu0.5",
        "1:8.2p1-4ubuntu0.7",
        "1:8.2p1-4ubuntu0.8"
      ]
    }
  ],
  "aliases": [],
  "details": "It was discovered that OpenSSH has an observable discrepancy leading to an\ninformation leak in the algorithm negotiation. This update mitigates the\nissue by tweaking the client hostkey preference ordering algorithm to\nprefer the default ordering if the user has a key that matches the\nbest-preference default algorithm.\n",
  "id": "USN-6279-1",
  "modified": "2026-06-29T10:53:03Z",
  "published": "2023-08-09T06:08:18Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://ubuntu.com/security/notices/USN-6279-1"
    },
    {
      "type": "REPORT",
      "url": "https://launchpad.net/bugs/2030275"
    }
  ],
  "related": [],
  "schema_version": "1.7.0",
  "summary": "openssh update",
  "upstream": []
}



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