ubuntu-cve-2026-43994
Vulnerability from osv_ubuntu
Published
2026-06-18 21:16
Modified
2026-06-29 11:33
Summary
Details

Coturn is a free open source implementation of TURN and STUN Server. Versions prior to 4.10.0 contain a stack buffer overflow in decode_oauth_token_gcm(). A uint16_t nonce_len field read from an attacker-supplied OAuth access token (0-65535) is passed directly to memcpy() as the copy length into a 256-byte stack buffer (oauth_encrypted_block.nonce[256]) without bounds checking. The overflow occurs before AES-GCM authentication is verified, the attacker does not need to know the OAuth key or produce a valid AES-GCM token. Up to 735 bytes of attacker-controlled data are written past the buffer, may corrupt adjacent stack data, including control-flow data depending on compiler, ABI, and mitigations. Requires --oauth mode (non-default). This may provide a plausible RCE primitive depending on exploit mitigations; because coturn is widely deployed for WebRTC TURN/STUN and --oauth is commonly recommended, impact can be broad. This issue has been fixed in version 4.10.0.

Severity
8.1 (High)
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
9.8 (Critical)
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
N/A (UNKNOWN)
medium
References
To clipboard 

{
  "affected": [
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "coturn",
            "binary_version": "4.5.0.3-1ubuntu0.4"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:16.04:LTS",
        "name": "coturn",
        "purl": "pkg:deb/ubuntu/coturn@4.5.0.3-1ubuntu0.4?arch=source\u0026distro=xenial"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "4.4.5.4-2",
        "4.5.0.2-3",
        "4.5.0.3-1",
        "4.5.0.3-1build1",
        "4.5.0.3-1ubuntu0.2",
        "4.5.0.3-1ubuntu0.3",
        "4.5.0.3-1ubuntu0.4"
      ]
    },
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "coturn",
            "binary_version": "4.5.0.7-1ubuntu2.18.04.3"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:18.04:LTS",
        "name": "coturn",
        "purl": "pkg:deb/ubuntu/coturn@4.5.0.7-1ubuntu2.18.04.3?arch=source\u0026distro=bionic"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "4.5.0.6-1ubuntu2",
        "4.5.0.7-1ubuntu1",
        "4.5.0.7-1ubuntu2",
        "4.5.0.7-1ubuntu2.18.04.1",
        "4.5.0.7-1ubuntu2.18.04.2",
        "4.5.0.7-1ubuntu2.18.04.3"
      ]
    },
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "coturn",
            "binary_version": "4.5.1.1-1.1ubuntu0.20.04.2"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:20.04:LTS",
        "name": "coturn",
        "purl": "pkg:deb/ubuntu/coturn@4.5.1.1-1.1ubuntu0.20.04.2?arch=source\u0026distro=focal"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "4.5.1.1-1.1build1",
        "4.5.1.1-1.1build2",
        "4.5.1.1-1.1ubuntu0.20.04.1",
        "4.5.1.1-1.1ubuntu0.20.04.2"
      ]
    },
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "coturn",
            "binary_version": "4.5.2-3.1~ubuntu22.04.1"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:22.04:LTS",
        "name": "coturn",
        "purl": "pkg:deb/ubuntu/coturn@4.5.2-3.1~ubuntu22.04.1?arch=source\u0026distro=jammy"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "4.5.2-3",
        "4.5.2-3.1~ubuntu22.04.1"
      ]
    },
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "coturn",
            "binary_version": "4.6.1-1build4"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:24.04:LTS",
        "name": "coturn",
        "purl": "pkg:deb/ubuntu/coturn@4.6.1-1build4?arch=source\u0026distro=noble"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "4.6.1-1build1",
        "4.6.1-1build2",
        "4.6.1-1build3",
        "4.6.1-1build4"
      ]
    },
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "coturn",
            "binary_version": "4.6.1-2build1"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:25.10",
        "name": "coturn",
        "purl": "pkg:deb/ubuntu/coturn@4.6.1-2build1?arch=source\u0026distro=questing"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "4.6.1-2build1"
      ]
    },
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "coturn",
            "binary_version": "4.6.1-2build2"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:26.04:LTS",
        "name": "coturn",
        "purl": "pkg:deb/ubuntu/coturn@4.6.1-2build2?arch=source\u0026distro=resolute"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "4.6.1-2build1",
        "4.6.1-2build2"
      ]
    }
  ],
  "aliases": [],
  "details": "Coturn is a free open source implementation of TURN and STUN Server. Versions prior to 4.10.0 contain a stack buffer overflow in decode_oauth_token_gcm(). A uint16_t nonce_len field read from an attacker-supplied OAuth access token (0-65535) is passed directly to memcpy() as the copy length into a 256-byte stack buffer (oauth_encrypted_block.nonce[256]) without bounds checking. The overflow occurs before AES-GCM authentication is verified, the attacker does not need to know the OAuth key or produce a valid AES-GCM token. Up to 735 bytes of attacker-controlled data are written past the buffer, may corrupt adjacent stack data, including control-flow data depending on compiler, ABI, and mitigations. Requires --oauth mode (non-default). This may provide a plausible RCE primitive depending on exploit mitigations; because coturn is widely deployed for WebRTC TURN/STUN and --oauth is commonly recommended, impact can be broad. This issue has been fixed in version 4.10.0.",
  "id": "UBUNTU-CVE-2026-43994",
  "modified": "2026-06-29T11:33:49Z",
  "published": "2026-06-18T21:16:00Z",
  "references": [
    {
      "type": "REPORT",
      "url": "https://ubuntu.com/security/CVE-2026-43994"
    },
    {
      "type": "REPORT",
      "url": "https://www.cve.org/CVERecord?id=CVE-2026-43994"
    },
    {
      "type": "REPORT",
      "url": "https://github.com/coturn/coturn/security/advisories/GHSA-74pg-rfh2-5qw5"
    },
    {
      "type": "REPORT",
      "url": "https://github.com/coturn/coturn/commit/5ca467e70915c033f371cd7a9742759c68f56363"
    },
    {
      "type": "REPORT",
      "url": "https://github.com/coturn/coturn/releases/tag/4.10.0"
    }
  ],
  "related": [],
  "schema_version": "1.7.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H",
      "type": "CVSS_V3"
    },
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
      "type": "CVSS_V3"
    },
    {
      "score": "medium",
      "type": "Ubuntu"
    }
  ],
  "upstream": [
    "CVE-2026-43994"
  ]
}



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