Medium [CVE-2026-68554] Unauthorized actions or resource manipulation via STUN request modification
This medium-severity Red Hat Linux advisory covers CVE-2026-68554.
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Summary
Coturn is a free open source implementation of TURN and STUN Server. Prior to 4.15.0, an on-path attacker can append attributes after MESSAGE-INTEGRITY to an authenticated STUN request on plain UDP or TCP, adjust the STUN header length, and recompute the unkeyed FINGERPRINT while the original HMAC remains valid because it covers only the message prefix.
Server-side parsing in src/server/ns_turn_server.c continues past MESSAGE-INTEGRITY through handle_turn_allocate(), handle_turn_create_permission(), handle_turn_refresh(), and handle_turn_command(), allowing trailing LIFETIME, XOR-PEER-ADDRESS, or ORIGIN attributes to override allocation lifetime, inject a permission, or bypass the origin check.
TLS and DTLS deployments prevent this in-transit modification. This issue is fixed in version 4.15.0.
This allows the attacker to modify the request by overriding allocation lifetime, injecting permissions, or bypassing origin checks, potentially leading to unauthorized actions or resource manipulation. Coturn is not shipped in any Red Hat product.
Red Hat severity: Moderate — CVSS 5.4 (CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:L). Weakness: CWE-354.
- < 4.15.0
Official advisory · high-confidence parse· fetched 1 hour ago·verify at source
Mitigation checklist
- Upgrade to coturn version 4.15.0 or later. Deployments using TLS or DTLS transports are not vulnerable to this issue.
Official advisory · high-confidence parse· fetched 1 hour ago·verify at source
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