Coturn: MOBILITY-TICKET session-resume authorization bypass allows cross-user TURN allocation takeover

Summary

CVECVE-2026-65981
StatePUBLISHED
AssignerGitHub_M
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-07-31 21:17:31 UTC
Updated2026-07-31 21:17:31 UTC
DescriptionCoturn 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.

Risk And Classification

Primary CVSS: v3.1 7.1 HIGH from [email protected]

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

Problem Types: CWE-639 | CWE-639 CWE-639: Authorization Bypass Through User-Controlled Key


VersionSourceTypeScoreSeverityVector
3.1[email protected]Secondary7.1HIGHCVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:L
3.1CNADECLARED7.1HIGHCVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:L

CVSS v3.1 Breakdown

Attack Vector
Network
Attack Complexity
High
Privileges Required
Low
User Interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
Low

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

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Coturn Coturn affected < 4.15.0 Not specified

References

ReferenceSourceLinkTags
github.com/coturn/coturn/security/advisories/GHSA-69wx-x7x6-pjj8 [email protected] github.com
github.com/coturn/coturn/commit/37df0513168f830a7c9ce0a411db0300fa182f05 [email protected] github.com
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