{"id":"CVE-2026-43994","summary":"Coturn: Stack buffer overflow in decode_oauth_token_gcm()","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.","aliases":["GHSA-74pg-rfh2-5qw5"],"modified":"2026-07-08T08:13:29.538111999Z","published":"2026-06-18T19:44:46.575Z","database_specific":{"osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/43xxx/CVE-2026-43994.json","cwe_ids":["CWE-120"],"cna_assigner":"GitHub_M"},"references":[{"type":"WEB","url":"https://github.com/coturn/coturn/releases/tag/4.10.0"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/43xxx/CVE-2026-43994.json"},{"type":"ADVISORY","url":"https://github.com/coturn/coturn/security/advisories/GHSA-74pg-rfh2-5qw5"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-43994"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://github.com/coturn/coturn","events":[{"introduced":"0"},{"fixed":"8e2c575229de615a3414bd9c81215c3b040471b4"}],"database_specific":{"source":["AFFECTED_FIELD","CPE_RANGE","REFERENCES"],"extracted_events":[{"introduced":"0"},{"fixed":"4.10.0"}],"cpe":"cpe:2.3:a:coturn_project:coturn:*:*:*:*:*:*:*:*"}}],"versions":["docker/4.9.0-r0","4.9.0","docker/4.8.0-r1","docker/4.8.0-r0","4.8.0","docker/4.7.0-r4","docker/4.7.0-r3","docker/4.7.0-r2","docker/4.7.0-r1","docker/4.7.0-r0","4.7.0","docker/4.6.3-r3","docker/4.6.3-r2","docker/4.6.3-r1","docker/4.6.3-r0","4.6.3","docker/4.6.2-r13","docker/4.6.2-r12","docker/4.6.2-r11","docker/4.6.2-r10","docker/4.6.2-r9","docker/4.6.2-r8","docker/4.6.2-r7","docker/4.6.2-r6","docker/4.6.2-r5","docker/4.6.2-r4","docker/4.6.2-r3","docker/4.6.2-r2","docker/4.6.2-r1","docker/4.6.2-r0","4.6.2","docker/4.6.1-r3","docker/4.6.1-r2","docker/4.6.1-r1","docker/4.6.1-r0","docker/4.6.0-r1","docker/4.6.0-r0","4.6.0","docker/4.5.2-r14","docker/4.5.2-r13","docker/4.5.2-r12","docker/4.5.2-r11","docker/4.5.2-r10","docker/4.5.2-r9","docker/4.5.2-r8","docker/4.5.2-r7","docker/4.5.2-r6","docker/4.5.2-r0","4.5.2","4.5.1.3","4.5.1.2","4.5.1.1","4.5.1.0","4.5.0.7","4.5.0.6","4.5.0.5","4.5.0.4","4.5.0.3","4.5.0.2","4.5.0.1","4.4.5.4","4.4.5.3"],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-43994.json"}}],"schema_version":"1.7.5","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H"}]}