Vulnerability-Lookup

UBUNTU-CVE-2026-43994 (CVE-2026-43994)

Vulnerability from osv_ubuntu – Published: 2026-06-18 21:16 – Updated: 2026-06-29 11:33 – Source website

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

URL

Type

	https://ubuntu.com/security/CVE-2026-43994	REPORT
	https://www.cve.org/CVERecord?id=CVE-2026-43994	REPORT
	https://github.com/coturn/coturn/security/advisor…	REPORT
	https://github.com/coturn/coturn/commit/5ca467e70…	REPORT
	https://github.com/coturn/coturn/releases/tag/4.10.0	REPORT

JSON

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"
  ]
}

CVE-2026-43994 (GCVE-0-2026-43994)

Vulnerability from cvelistv5 – Published: 2026-06-18 19:44 – Updated: 2026-06-22 18:06

Title

Coturn: Stack buffer overflow in decode_oauth_token_gcm()

Summary

Severity

8.1 (High)


                        
                          CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H

SSVC

Exploitation: poc Automatable: no Technical Impact: total

CISA Coordinator · CISA-ADP (v2.0.3)

Decision recorded 2026-06-22 18:06 UTC

CWE

CWE-120 - Buffer Copy without Checking Size of Input ('Classic Buffer Overflow')

Assigner

GitHub_M mitre root

References

2 references

URL	Tags
https://github.com/coturn/coturn/security/advisor…	x_refsource_CONFIRM
https://github.com/coturn/coturn/releases/tag/4.10.0	x_refsource_MISC

Impacted products

1 product

Vendor	Product	Version
coturn	coturn	Affected: < 4.10.0

Show details on NVD website

JSON

To clipboard

{
  "containers": {
    "adp": [
      {
        "metrics": [
          {
            "other": {
              "content": {
                "id": "CVE-2026-43994",
                "options": [
                  {
                    "Exploitation": "poc"
                  },
                  {
                    "Automatable": "no"
                  },
                  {
                    "Technical Impact": "total"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2026-06-22T18:06:24.207624Z",
                "version": "2.0.3"
              },
              "type": "ssvc"
            }
          }
        ],
        "providerMetadata": {
          "dateUpdated": "2026-06-22T18:06:27.688Z",
          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
        },
        "references": [
          {
            "tags": [
              "exploit"
            ],
            "url": "https://github.com/coturn/coturn/security/advisories/GHSA-74pg-rfh2-5qw5"
          }
        ],
        "title": "CISA ADP Vulnrichment"
      }
    ],
    "cna": {
      "affected": [
        {
          "product": "coturn",
          "vendor": "coturn",
          "versions": [
            {
              "status": "affected",
              "version": "\u003c 4.10.0"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "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."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "attackComplexity": "HIGH",
            "attackVector": "NETWORK",
            "availabilityImpact": "HIGH",
            "baseScore": 8.1,
            "baseSeverity": "HIGH",
            "confidentialityImpact": "HIGH",
            "integrityImpact": "HIGH",
            "privilegesRequired": "NONE",
            "scope": "UNCHANGED",
            "userInteraction": "NONE",
            "vectorString": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H",
            "version": "3.1"
          }
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "cweId": "CWE-120",
              "description": "CWE-120: Buffer Copy without Checking Size of Input (\u0027Classic Buffer Overflow\u0027)",
              "lang": "en",
              "type": "CWE"
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          ]
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      "providerMetadata": {
        "dateUpdated": "2026-06-18T19:44:46.575Z",
        "orgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
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      "source": {
        "advisory": "GHSA-74pg-rfh2-5qw5",
        "discovery": "UNKNOWN"
      },
      "title": "Coturn: Stack buffer overflow in decode_oauth_token_gcm()"
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  "cveMetadata": {
    "assignerOrgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
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    "datePublished": "2026-06-18T19:44:46.575Z",
    "dateReserved": "2026-05-04T20:24:31.917Z",
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    "state": "PUBLISHED"
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  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}

Sightings

Author	Source	Type	Date	Other

Nomenclature

Seen: The vulnerability was mentioned, discussed, or observed by the user.
Confirmed: The vulnerability has been validated from an analyst's perspective.
Published Proof of Concept: A public proof of concept is available for this vulnerability.
Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
Not confirmed: The user expressed doubt about the validity of the vulnerability.
Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.

Detection rules are retrieved from Rulezet.

The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base model, served locally by ML-Gateway. They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
Browse all ATT&CK techniques and the vulnerabilities related to each.

Related by attack behaviour

Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.