USN-8951-1 (UBUNTU-CVE-2020-22217)

Vulnerability from osv_ubuntu – Published: 2026-10-21 18:20 – Updated: 2026-10-21 18:20 – Source website
VLAI
Summary
c-ares vulnerabilities
Details

It was discovered that c-ares incorrectly parsed certain SOA replies. A remote attacker could possibly use this issue to cause c-ares to crash, resulting in a denial of service. This issue only affected Ubuntu 16.04 LTS and Ubuntu 18.04 LTS. (CVE-2020-22217)

It was discovered that c-ares incorrectly handled certain sortlist strings. A remote attacker could possibly use this issue to cause c-ares to crash, resulting in a denial of service, or execute arbitrary code. This issue only affected Ubuntu 16.04 LTS. (CVE-2022-4904)

It was discovered that c-ares did not properly limit DNS compression pointer hops or assembled name lengths when parsing DNS names. A remote attacker could possibly use this issue to cause c-ares to use excessive resources, resulting in a denial of service. (CVE-2026-69184)

It was discovered that c-ares did not properly validate record count fields before allocating memory when parsing DNS responses. A remote attacker could possibly use this issue to cause c-ares to use excessive resources, resulting in a denial of service. This issue only affected Ubuntu 24.04 LTS and Ubuntu 26.04 LTS. (CVE-2026-69186)

References
To clipboard 

{
  "affected": [
    {
      "database_specific": {
        "cves_map": {
          "cves": [
            {
              "id": "CVE-2020-22217",
              "severity": [
                {
                  "score": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H",
                  "type": "CVSS_V3"
                },
                {
                  "score": "medium",
                  "type": "Ubuntu"
                }
              ]
            },
            {
              "id": "CVE-2022-4904",
              "severity": [
                {
                  "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:H",
                  "type": "CVSS_V3"
                },
                {
                  "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:H",
                  "type": "CVSS_V3"
                },
                {
                  "score": "medium",
                  "type": "Ubuntu"
                }
              ]
            },
            {
              "id": "CVE-2026-69184",
              "severity": [
                {
                  "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
                  "type": "CVSS_V3"
                },
                {
                  "score": "medium",
                  "type": "Ubuntu"
                }
              ]
            }
          ],
          "ecosystem": "Ubuntu:Pro:16.04:LTS"
        }
      },
      "ecosystem_specific": {
        "availability": "Available with Ubuntu Pro with Legacy support add-on: https://ubuntu.com/pro",
        "binaries": [
          {
            "binary_name": "libc-ares2",
            "binary_version": "1.10.0-3ubuntu0.2+esm4"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:Pro:16.04:LTS",
        "name": "c-ares",
        "purl": "pkg:deb/ubuntu/c-ares@1.10.0-3ubuntu0.2+esm4?arch=source\u0026distro=esm-infra-legacy/xenial"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "1.10.0-3ubuntu0.2+esm4"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "1.10.0-2",
        "1.10.0-3",
        "1.10.0-3ubuntu0.1",
        "1.10.0-3ubuntu0.2",
        "1.10.0-3ubuntu0.2+esm1",
        "1.10.0-3ubuntu0.2+esm2",
        "1.10.0-3ubuntu0.2+esm3"
      ]
    },
    {
      "database_specific": {
        "cves_map": {
          "cves": [
            {
              "id": "CVE-2020-22217",
              "severity": [
                {
                  "score": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H",
                  "type": "CVSS_V3"
                },
                {
                  "score": "medium",
                  "type": "Ubuntu"
                }
              ]
            },
            {
              "id": "CVE-2026-69184",
              "severity": [
                {
                  "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
                  "type": "CVSS_V3"
                },
                {
                  "score": "medium",
                  "type": "Ubuntu"
                }
              ]
            }
          ],
          "ecosystem": "Ubuntu:Pro:18.04:LTS"
        }
      },
      "ecosystem_specific": {
        "availability": "Available with Ubuntu Pro (Infra-only): https://ubuntu.com/pro",
        "binaries": [
          {
            "binary_name": "libc-ares2",
            "binary_version": "1.14.0-1ubuntu0.2+esm3"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:Pro:18.04:LTS",
        "name": "c-ares",
        "purl": "pkg:deb/ubuntu/c-ares@1.14.0-1ubuntu0.2+esm3?arch=source\u0026distro=esm-infra/bionic"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "1.14.0-1ubuntu0.2+esm3"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "1.13.0-2",
        "1.13.0-3",
        "1.14.0-1",
        "1.14.0-1ubuntu0.1",
        "1.14.0-1ubuntu0.2",
        "1.14.0-1ubuntu0.2+esm1",
        "1.14.0-1ubuntu0.2+esm2"
      ]
    },
    {
      "database_specific": {
        "cves_map": {
          "cves": [
            {
              "id": "CVE-2026-69184",
              "severity": [
                {
                  "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
                  "type": "CVSS_V3"
                },
                {
                  "score": "medium",
                  "type": "Ubuntu"
                }
              ]
            }
          ],
          "ecosystem": "Ubuntu:Pro:20.04:LTS"
        }
      },
      "ecosystem_specific": {
        "availability": "Available with Ubuntu Pro (Infra-only): https://ubuntu.com/pro",
        "binaries": [
          {
            "binary_name": "libc-ares2",
            "binary_version": "1.15.0-1ubuntu0.5+esm1"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:Pro:20.04:LTS",
        "name": "c-ares",
        "purl": "pkg:deb/ubuntu/c-ares@1.15.0-1ubuntu0.5+esm1?arch=source\u0026distro=esm-infra/focal"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "1.15.0-1ubuntu0.5+esm1"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "1.15.0-1build1",
        "1.15.0-1ubuntu0.1",
        "1.15.0-1ubuntu0.2",
        "1.15.0-1ubuntu0.3",
        "1.15.0-1ubuntu0.4",
        "1.15.0-1ubuntu0.5"
      ]
    },
    {
      "database_specific": {
        "cves_map": {
          "cves": [
            {
              "id": "CVE-2026-69184",
              "severity": [
                {
                  "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
                  "type": "CVSS_V3"
                },
                {
                  "score": "medium",
                  "type": "Ubuntu"
                }
              ]
            }
          ],
          "ecosystem": "Ubuntu:22.04:LTS"
        }
      },
      "ecosystem_specific": {
        "availability": "No subscription required",
        "binaries": [
          {
            "binary_name": "libc-ares2",
            "binary_version": "1.18.1-1ubuntu0.22.04.4"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:22.04:LTS",
        "name": "c-ares",
        "purl": "pkg:deb/ubuntu/c-ares@1.18.1-1ubuntu0.22.04.4?arch=source\u0026distro=jammy"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "1.18.1-1ubuntu0.22.04.4"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "1.17.1-1ubuntu1",
        "1.18.1-1",
        "1.18.1-1build1",
        "1.18.1-1ubuntu0.22.04.1",
        "1.18.1-1ubuntu0.22.04.2",
        "1.18.1-1ubuntu0.22.04.3"
      ]
    },
    {
      "database_specific": {
        "cves_map": {
          "cves": [
            {
              "id": "CVE-2026-69184",
              "severity": [
                {
                  "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
                  "type": "CVSS_V3"
                },
                {
                  "score": "medium",
                  "type": "Ubuntu"
                }
              ]
            },
            {
              "id": "CVE-2026-69186",
              "severity": [
                {
                  "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L",
                  "type": "CVSS_V3"
                },
                {
                  "score": "medium",
                  "type": "Ubuntu"
                }
              ]
            }
          ],
          "ecosystem": "Ubuntu:24.04:LTS"
        }
      },
      "ecosystem_specific": {
        "availability": "No subscription required",
        "binaries": [
          {
            "binary_name": "libcares2",
            "binary_version": "1.27.0-1.0ubuntu1.1"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:24.04:LTS",
        "name": "c-ares",
        "purl": "pkg:deb/ubuntu/c-ares@1.27.0-1.0ubuntu1.1?arch=source\u0026distro=noble"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "1.27.0-1.0ubuntu1.1"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "1.19.1-3",
        "1.20.1-1",
        "1.26.0-1",
        "1.27.0-1",
        "1.27.0-1.0ubuntu1"
      ]
    },
    {
      "database_specific": {
        "cves_map": {
          "cves": [
            {
              "id": "CVE-2026-69184",
              "severity": [
                {
                  "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
                  "type": "CVSS_V3"
                },
                {
                  "score": "medium",
                  "type": "Ubuntu"
                }
              ]
            },
            {
              "id": "CVE-2026-69186",
              "severity": [
                {
                  "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L",
                  "type": "CVSS_V3"
                },
                {
                  "score": "medium",
                  "type": "Ubuntu"
                }
              ]
            }
          ],
          "ecosystem": "Ubuntu:26.04:LTS"
        }
      },
      "ecosystem_specific": {
        "availability": "No subscription required",
        "binaries": [
          {
            "binary_name": "libc-ares2",
            "binary_version": "1.34.6-1ubuntu0.2"
          },
          {
            "binary_name": "libcares2",
            "binary_version": "1.34.6-1ubuntu0.2"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:26.04:LTS",
        "name": "c-ares",
        "purl": "pkg:deb/ubuntu/c-ares@1.34.6-1ubuntu0.2?arch=source\u0026distro=resolute"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "1.34.6-1ubuntu0.2"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "1.34.5-1",
        "1.34.6-1",
        "1.34.6-1ubuntu0.1"
      ]
    }
  ],
  "aliases": [],
  "details": "It was discovered that c-ares incorrectly parsed certain SOA replies. A\nremote attacker could possibly use this issue to cause c-ares to crash,\nresulting in a denial of service. This issue only affected Ubuntu 16.04 LTS\nand Ubuntu 18.04 LTS. (CVE-2020-22217)\n\nIt was discovered that c-ares incorrectly handled certain sortlist strings.\nA remote attacker could possibly use this issue to cause c-ares to crash,\nresulting in a denial of service, or execute arbitrary code. This issue\nonly affected Ubuntu 16.04 LTS. (CVE-2022-4904)\n\nIt was discovered that c-ares did not properly limit DNS compression\npointer hops or assembled name lengths when parsing DNS names. A remote\nattacker could possibly use this issue to cause c-ares to use excessive\nresources, resulting in a denial of service. (CVE-2026-69184)\n\nIt was discovered that c-ares did not properly validate record count fields\nbefore allocating memory when parsing DNS responses. A remote attacker\ncould possibly use this issue to cause c-ares to use excessive resources,\nresulting in a denial of service. This issue only affected Ubuntu 24.04 LTS\nand Ubuntu 26.04 LTS. (CVE-2026-69186)",
  "id": "USN-8951-1",
  "modified": "2026-10-21T18:20:42Z",
  "published": "2026-10-21T18:20:42Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://ubuntu.com/security/notices/USN-8951-1"
    },
    {
      "type": "REPORT",
      "url": "https://ubuntu.com/security/CVE-2020-22217"
    },
    {
      "type": "REPORT",
      "url": "https://ubuntu.com/security/CVE-2022-4904"
    },
    {
      "type": "REPORT",
      "url": "https://ubuntu.com/security/CVE-2026-69184"
    },
    {
      "type": "REPORT",
      "url": "https://ubuntu.com/security/CVE-2026-69186"
    }
  ],
  "related": [],
  "schema_version": "1.7.0",
  "summary": "c-ares vulnerabilities",
  "upstream": [
    "UBUNTU-CVE-2020-22217",
    "UBUNTU-CVE-2022-4904",
    "UBUNTU-CVE-2026-69184",
    "UBUNTU-CVE-2026-69186"
  ]
}



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