Medium, CVSS 5.6crates.ioAmendedPublished
mediasoup: SCTP state cookie lacks cryptographic authentication, enabling unauthorized association establishment (RFC 9260 violation)
CVE-2026-55663 · GHSA-p7x2-g5cq-fhmq
- Affected
- crates.io mediasoup >= 0.22.0, <= 0.22.4
- Fixed in
- 0.22.5· Vendor fix available
- Issue
- mediasoup's built-in SCTP stack (introduced in v3.20.0) authenticates SCTP state cookies using only hardcoded magic byte sequences rather than a per-instance HMAC keyed with a secret, violating RFC 9260 Section 5.1.3. An on-path attacker targeting a PlainTransport with SCTP enabled (and no SRTP/DTLS protection) can craft a forged COOKIE-ECHO chunk that passes all validation, establishing an unauthorized SCTP association and gaining the ability to inject DataChannel messages as a trusted peer. Details RFC 9260 Section 5.1.3 states: "An endpoint MUST use a one-time-use secret key to protect the State Cookie." The mediasoup implementation ignores this requirement. The state cookie is defined in worker/include/RTC/SCTP/association/StateCookie.hpp with the following structure (44 bytes total): - Offset 0: Magic1 = "msworker" (hardcoded, 8 bytes) - Offset 8: localVerificationTag (4 bytes, attacker-controlled) - Offset 12: remoteVerificationTag (4 bytes, attacker-controlled) -…
Recommended action: Upgrade to 0.22.5 or later, then redeploy and verify.A vendor fix does not resolve your finding until you verify it in your own systems.