{"id":"CVE-2026-65981","summary":"Coturn: MOBILITY-TICKET session-resume authorization bypass allows cross-user TURN allocation takeover","details":"Coturn is a free open source implementation of TURN and STUN Server. Prior to 4.15.0, a server using --mobility authenticates a resumed REFRESH request with the resuming user's credentials but does not verify that identity against the original allocation owner, allowing an authenticated attacker who obtains a victim MOBILITY-TICKET to receive and inject relayed traffic and consume the victim's quota. In the handle_turn_refresh resume branch, the victim allocation (orig_ss) is located solely by the attacker-controlled mobile id, and credentials are only adopted (via copy_auth_parameters) when the resuming session is unauthenticated. Because the attacker's session already has hmackey_set set to 1 from its own prior authentication (which is never reset for long-term-credential sessions), the credential copy is skipped and check_stun_auth validates the REFRESH against the attacker's own identity rather than the allocation owner's. This issue is fixed in version 4.15.0.","aliases":["GHSA-69wx-x7x6-pjj8"],"modified":"2026-08-07T21:13:19.392267Z","published":"2026-07-31T21:00:02.893Z","database_specific":{"cna_assigner":"GitHub_M","cwe_ids":["CWE-639"],"osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/65xxx/CVE-2026-65981.json"},"references":[{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/65xxx/CVE-2026-65981.json"},{"type":"ADVISORY","url":"https://github.com/coturn/coturn/security/advisories/GHSA-69wx-x7x6-pjj8"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-65981"},{"type":"FIX","url":"https://github.com/coturn/coturn/commit/37df0513168f830a7c9ce0a411db0300fa182f05"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://github.com/coturn/coturn","events":[{"introduced":"0"},{"fixed":"37df0513168f830a7c9ce0a411db0300fa182f05"}],"database_specific":{"extracted_events":[{"introduced":"0"},{"fixed":"4.15.0"}],"source":["AFFECTED_FIELD","REFERENCES"]}}],"versions":["docker/4.14.0-r0","4.14.0","docker/4.13.1-r0","docker/4.13.0-r0","4.13.1","4.13.0","docker/4.12.0-r0","4.12.0","docker/4.11.0-r0","4.11.0","docker/4.10.0-r1","docker/4.10.0-r0","4.10.0","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-2026-65981.json","vanir_signatures_modified":"2026-08-07T21:13:19Z","vanir_signatures":[{"id":"CVE-2026-65981-ae564408","signature_type":"Function","signature_version":"v1","source":"https://github.com/coturn/coturn/commit/37df0513168f830a7c9ce0a411db0300fa182f05","target":{"file":"src/server/ns_turn_server.c","function":"handle_turn_refresh"},"deprecated":false,"digest":{"function_hash":"197916663795514868159840160029149056090","length":8428}},{"source":"https://github.com/coturn/coturn/commit/37df0513168f830a7c9ce0a411db0300fa182f05","target":{"file":"src/server/ns_turn_server.c"},"deprecated":false,"digest":{"threshold":0.9,"line_hashes":["203063699980262977910702699095187416931","264744890826765136726751489544041317691","31165866878218289787918713121085215238","150473482546220356451710947115947676403","239544868063577559894702676367029653670","251465978124799886783172158590206497212"]},"id":"CVE-2026-65981-b100d531","signature_type":"Line","signature_version":"v1"}]}}],"schema_version":"1.8.0","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:L"}]}