{
  "containers": {
    "cna": {
      "affected": [
        {
          "product": "coturn",
          "vendor": "coturn",
          "versions": [
            {
              "status": "affected",
              "version": "\u003c 4.9.0"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "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."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "attackComplexity": "LOW",
            "attackVector": "NETWORK",
            "availabilityImpact": "NONE",
            "baseScore": 7.2,
            "baseSeverity": "HIGH",
            "confidentialityImpact": "LOW",
            "integrityImpact": "LOW",
            "privilegesRequired": "NONE",
            "scope": "CHANGED",
            "userInteraction": "NONE",
            "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:L/A:N",
            "version": "3.1"
          }
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "cweId": "CWE-284",
              "description": "CWE-284: Improper Access Control",
              "lang": "en",
              "type": "CWE"
            }
          ]
        },
        {
          "descriptions": [
            {
              "cweId": "CWE-441",
              "description": "CWE-441: Unintended Proxy or Intermediary (\u0027Confused Deputy\u0027)",
              "lang": "en",
              "type": "CWE"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-02-25T04:04:17.009Z",
        "orgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
        "shortName": "GitHub_M"
      },
      "references": [
        {
          "name": "https://github.com/coturn/coturn/security/advisories/GHSA-j8mm-mpf8-gvjg",
          "tags": [
            "x_refsource_CONFIRM"
          ],
          "url": "https://github.com/coturn/coturn/security/advisories/GHSA-j8mm-mpf8-gvjg"
        },
        {
          "name": "https://github.com/coturn/coturn/security/advisories/GHSA-6g6j-r9rf-cm7p",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/coturn/coturn/security/advisories/GHSA-6g6j-r9rf-cm7p"
        },
        {
          "name": "https://github.com/coturn/coturn/commit/b80eb898ba26552600770162c26a8ae7f3661b0b",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/coturn/coturn/commit/b80eb898ba26552600770162c26a8ae7f3661b0b"
        }
      ],
      "source": {
        "advisory": "GHSA-j8mm-mpf8-gvjg",
        "discovery": "UNKNOWN"
      },
      "title": "Coturn: IPv4-mapped IPv6 (::ffff:0:0/96) bypasses denied-peer-ip ACL"
    }
  },
  "cveMetadata": {
    "assignerOrgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
    "assignerShortName": "GitHub_M",
    "cveId": "CVE-2026-27624",
    "datePublished": "2026-02-25T04:04:17.009Z",
    "dateReserved": "2026-02-20T22:02:30.027Z",
    "dateUpdated": "2026-02-25T04:04:17.009Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}