usn-6560-1
Vulnerability from osv_ubuntu
Published
2023-12-19 13:02
Modified
2026-04-27 14:11
Summary
openssh vulnerabilities
Details

Fabian Bäumer, Marcus Brinkmann, Jörg Schwenk discovered that the SSH protocol was vulnerable to a prefix truncation attack. If a remote attacker was able to intercept SSH communications, extension negotiation messages could be truncated, possibly leading to certain algorithms and features being downgraded. This issue is known as the Terrapin attack. This update adds protocol extensions to mitigate this issue. (CVE-2023-48795)

Luci Stanescu discovered that OpenSSH incorrectly added destination constraints when smartcard keys were added to ssh-agent, contrary to expectations. This issue only affected Ubuntu 22.04 LTS, and Ubuntu 23.04. (CVE-2023-28531)

References
To clipboard 

{
  "affected": [
    {
      "database_specific": {
        "cves_map": {
          "cves": [
            {
              "id": "CVE-2023-48795",
              "severity": [
                {
                  "score": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N",
                  "type": "CVSS_V3"
                },
                {
                  "score": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N",
                  "type": "CVSS_V3"
                },
                {
                  "score": "medium",
                  "type": "Ubuntu"
                }
              ]
            }
          ],
          "ecosystem": "Ubuntu:20.04:LTS"
        }
      },
      "ecosystem_specific": {
        "availability": "No subscription required",
        "binaries": [
          {
            "binary_name": "openssh-client",
            "binary_version": "1:8.2p1-4ubuntu0.10"
          },
          {
            "binary_name": "openssh-server",
            "binary_version": "1:8.2p1-4ubuntu0.10"
          },
          {
            "binary_name": "openssh-sftp-server",
            "binary_version": "1:8.2p1-4ubuntu0.10"
          },
          {
            "binary_name": "openssh-tests",
            "binary_version": "1:8.2p1-4ubuntu0.10"
          },
          {
            "binary_name": "ssh",
            "binary_version": "1:8.2p1-4ubuntu0.10"
          },
          {
            "binary_name": "ssh-askpass-gnome",
            "binary_version": "1:8.2p1-4ubuntu0.10"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:20.04:LTS",
        "name": "openssh",
        "purl": "pkg:deb/ubuntu/openssh@1:8.2p1-4ubuntu0.10?arch=source\u0026distro=focal"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "1:8.2p1-4ubuntu0.10"
            }
          ],
          "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",
        "1:8.2p1-4ubuntu0.9"
      ]
    },
    {
      "database_specific": {
        "cves_map": {
          "cves": [
            {
              "id": "CVE-2023-28531",
              "severity": [
                {
                  "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
                  "type": "CVSS_V3"
                },
                {
                  "score": "low",
                  "type": "Ubuntu"
                }
              ]
            },
            {
              "id": "CVE-2023-48795",
              "severity": [
                {
                  "score": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N",
                  "type": "CVSS_V3"
                },
                {
                  "score": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N",
                  "type": "CVSS_V3"
                },
                {
                  "score": "medium",
                  "type": "Ubuntu"
                }
              ]
            }
          ],
          "ecosystem": "Ubuntu:22.04:LTS"
        }
      },
      "ecosystem_specific": {
        "availability": "No subscription required",
        "binaries": [
          {
            "binary_name": "openssh-client",
            "binary_version": "1:8.9p1-3ubuntu0.5"
          },
          {
            "binary_name": "openssh-server",
            "binary_version": "1:8.9p1-3ubuntu0.5"
          },
          {
            "binary_name": "openssh-sftp-server",
            "binary_version": "1:8.9p1-3ubuntu0.5"
          },
          {
            "binary_name": "openssh-tests",
            "binary_version": "1:8.9p1-3ubuntu0.5"
          },
          {
            "binary_name": "ssh",
            "binary_version": "1:8.9p1-3ubuntu0.5"
          },
          {
            "binary_name": "ssh-askpass-gnome",
            "binary_version": "1:8.9p1-3ubuntu0.5"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:22.04:LTS",
        "name": "openssh",
        "purl": "pkg:deb/ubuntu/openssh@1:8.9p1-3ubuntu0.5?arch=source\u0026distro=jammy"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "1:8.9p1-3ubuntu0.5"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "1:8.4p1-6ubuntu2",
        "1:8.7p1-2",
        "1:8.7p1-2build1",
        "1:8.7p1-4",
        "1:8.8p1-1",
        "1:8.9p1-3",
        "1:8.9p1-3ubuntu0.1",
        "1:8.9p1-3ubuntu0.3",
        "1:8.9p1-3ubuntu0.4"
      ]
    }
  ],
  "aliases": [],
  "details": "Fabian B\u00e4umer, Marcus Brinkmann, J\u00f6rg Schwenk discovered that the SSH\nprotocol was vulnerable to a prefix truncation attack. If a remote attacker\nwas able to intercept SSH communications, extension negotiation messages\ncould be truncated, possibly leading to certain algorithms and features\nbeing downgraded. This issue is known as the Terrapin attack. This update\nadds protocol extensions to mitigate this issue. (CVE-2023-48795)\n\nLuci Stanescu discovered that OpenSSH incorrectly added destination\nconstraints when smartcard keys were added to ssh-agent, contrary to\nexpectations. This issue only affected Ubuntu 22.04 LTS, and Ubuntu 23.04.\n(CVE-2023-28531)\n",
  "id": "USN-6560-1",
  "modified": "2026-04-27T14:11:32Z",
  "published": "2023-12-19T13:02:10Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://ubuntu.com/security/notices/USN-6560-1"
    },
    {
      "type": "REPORT",
      "url": "https://ubuntu.com/security/CVE-2023-28531"
    },
    {
      "type": "REPORT",
      "url": "https://ubuntu.com/security/CVE-2023-48795"
    }
  ],
  "related": [],
  "schema_version": "1.7.0",
  "summary": "openssh vulnerabilities",
  "upstream": [
    "UBUNTU-CVE-2023-28531",
    "UBUNTU-CVE-2023-48795"
  ]
}



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