coturn — security advisory

{
  "id": "e38d7b8d19064a0e51d8508e10e77cfeb2803fd734897d9fc8478067eddc5a38",
  "url": "https://osv.dev/vulnerability/DEBIAN-CVE-2026-27624",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "DEBIAN-CVE-2026-27624",
    "summary": "Coturn is a free open source implementation of TURN and STUN Server. Coturn is commonly configured to block loopback and internal ranges using \"denied-peer-ip\" and/or default loopback restrictions. CVE-2020-26262 addressed bypasses involving \"0.0.0.0\", \"[::1]\" and \"[::]\", but IPv4-mapped IPv6 is not covered. When sending a \"CreatePermission\" or \"ChannelBind\" request with the \"XOR-PEER-ADDRESS\" value of \"::ffff:127.0.0.1\", a successful response is received, even though \"127.0.0.0/8\" is blocked via \"denied-peer-ip\". The root cause is that, prior to the updated fix implemented in version 4.9.0, three functions in \"src/client/ns_turn_ioaddr.c\" do not check \"IN6_IS_ADDR_V4MAPPED\". \"ioa_addr_is_loopback()\" checks \"127.x.x.x\" (AF_INET) and \"::1\" (AF_INET6), but not \"::ffff:127.0.0.1.\" \"ioa_addr_is_zero()\" checks \"0.0.0.0\" and \"::\", but not \"::ffff:0.0.0.0.\" \"addr_less_eq()\" used by \"ioa_addr_in_range()\" for \"denied-peer-ip\" matching: when the range is AF_INET and the peer is AF_INET6, the comparison returns 0 without extracting the embedded IPv4. Version 4.9.0 contains an updated fix to address the bypass of the fix for CVE-2020-26262.",
    "evidence": "osv:DEBIAN-CVE-2026-27624",
    "products": [
      {
        "name": {
          "value": "coturn",
          "evidence": "/affected/0/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [],
        "affected_versions": [
          {
            "value": "4.12.0-1",
            "evidence": "/affected/0/versions"
          },
          {
            "value": "4.14.0-1",
            "evidence": "/affected/0/versions"
          },
          {
            "value": "4.15.0-1",
            "evidence": "/affected/0/versions"
          },
          {
            "value": "4.18.0-1",
            "evidence": "/affected/0/versions"
          },
          {
            "value": "4.6.1-1",
            "evidence": "/affected/0/versions"
          },
          {
            "value": "4.6.1-2",
            "evidence": "/affected/0/versions"
          }
        ]
      },
      {
        "name": {
          "value": "coturn",
          "evidence": "/affected/1/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [],
        "affected_versions": [
          {
            "value": "4.12.0-1",
            "evidence": "/affected/1/versions"
          },
          {
            "value": "4.14.0-1",
            "evidence": "/affected/1/versions"
          },
          {
            "value": "4.15.0-1",
            "evidence": "/affected/1/versions"
          },
          {
            "value": "4.18.0-1",
            "evidence": "/affected/1/versions"
          },
          {
            "value": "4.6.1-2",
            "evidence": "/affected/1/versions"
          }
        ]
      },
      {
        "name": {
          "value": "coturn",
          "evidence": "/affected/2/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "4.12.0-1",
            "evidence": "/affected/2/ranges"
          }
        ],
        "affected_versions": [
          {
            "value": "4.6.1-2",
            "evidence": "/affected/2/versions"
          }
        ]
      }
    ],
    "severity": "medium",
    "structured": {
      "id": "DEBIAN-CVE-2026-27624",
      "aliases": [
        "DEBIAN-CVE-2026-27624"
      ],
      "metrics": [
        {
          "type": "CVSS_V3",
          "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "0"
                }
              ]
            }
          ],
          "package": {
            "name": "coturn",
            "purl": "pkg:deb/debian/coturn?arch=source&distro=bookworm",
            "ecosystem": "Debian:12"
          },
          "versions": [
            "4.12.0-1",
            "4.14.0-1",
            "4.15.0-1",
            "4.18.0-1",
            "4.6.1-1",
            "4.6.1-2"
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-27624.json"
          },
          "ecosystem_specific": {
            "urgency": "not yet assigned"
          }
        },
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "0"
                }
              ]
            }
          ],
          "package": {
            "name": "coturn",
            "purl": "pkg:deb/debian/coturn?arch=source&distro=trixie",
            "ecosystem": "Debian:13"
          },
          "versions": [
            "4.12.0-1",
            "4.14.0-1",
            "4.15.0-1",
            "4.18.0-1",
            "4.6.1-2"
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-27624.json"
          },
          "ecosystem_specific": {
            "urgency": "not yet assigned"
          }
        },
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "0"
                },
                {
                  "fixed": "4.12.0-1"
                }
              ]
            }
          ],
          "package": {
            "name": "coturn",
            "purl": "pkg:deb/debian/coturn?arch=source&distro=forky",
            "ecosystem": "Debian:14"
          },
          "versions": [
            "4.6.1-2"
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/debian-osv/debian-cve-osv/DEBIAN-CVE-2026-27624.json"
          },
          "ecosystem_specific": {
            "urgency": "not yet assigned"
          }
        }
      ],
      "modified": "2026-10-10T16:00:06.179502161Z",
      "provider": "osv",
      "upstream": [
        "CVE-2026-27624"
      ],
      "references": [
        "https://security-tracker.debian.org/tracker/CVE-2026-27624"
      ]
    },
    "related_cves": [
      {
        "value": "CVE-2026-27624",
        "evidence": "/upstream"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 250465,
  "published_at": "2026-02-25T05:17:25.38+00:00"
}