{"schemaVersion":3,"id":"CVE-2026-65981","aliases":["UBUNTU-CVE-2026-65981","DEBIAN-CVE-2026-65981"],"status":"published","duplicateOf":null,"title":null,"description":"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.","dates":{"published":"2026-07-31T21:00:02.893Z","modified":"2026-08-05T13:44:34.433Z","reserved":null,"kevAdded":[],"kevDue":[]},"cvss":{"headline":{"score":7.1,"severity":"high","version":"3.1","versionLabel":"v3.1","source":"CVE.org","vector":"CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:L","computed":false,"selection":"backend-summary"},"metrics":[{"version":"3.1","versionLabel":"v3.1","source":"CVE.org","score":7.1,"severity":"high","vector":"CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:L","exploitability":null,"impact":null,"computed":false},{"version":"3.1","versionLabel":"v3.1","source":"OSV · Ubuntu","score":7.1,"severity":"high","vector":"CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:L","exploitability":4.1,"impact":9.2,"computed":true},{"version":"3.1","versionLabel":"v3.1","source":"OSV · 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