{"id":"CVE-2026-55663","state":"PUBLISHED","title":"mediasoup: SCTP state cookie lacks cryptographic authentication, enabling unauthorized association establishment (RFC 9260 violation)","description":"mediasoup is a WebRTC video conferencing system. From version 3.20.0 until 3.20.6 for the npm package and from 0.22.0 until 0.22.5 for the Rust crate, mediasoup's built-in SCTP stack authenticates state cookies using only the hardcoded msworker and 0xAD81 magic values instead of a per-instance secret and HMAC, contrary to RFC 9260 Section 5.1.3. The cookie structure and validation in worker/include/RTC/SCTP/association/StateCookie.hpp and worker/src/RTC/SCTP/association/StateCookie.cpp allow an on-path attacker targeting PlainTransport or PipeTransport with SCTP enabled and without DTLS protection to forge a COOKIE-ECHO whose packet verification tag matches the attacker-controlled localVerificationTag. The forged cookie passes StateCookie::IsMediasoupStateCookie() and Association::HandleReceivedCookieEchoChunk(), establishes an unauthorized SCTP association, and permits DataChannel message injection as a trusted peer. WebRtcTransport is not affected because its SCTP runs inside DTLS. This issue is fixed in npm version 3.20.6 and Rust crate version 0.22.5.","publishedAt":"2026-08-25T18:15:16.059Z","updatedAt":"2026-08-25T18:55:59.044Z","severity":{"score":5.6,"label":"Medium","version":"3.1","vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:L","source":"GitHub_M"},"assigner":"GitHub_M","products":["versatica mediasoup"],"affected":[{"vendor":"versatica","product":"mediasoup","versions":[{"version":">= 3.20.0, < 3.20.6","status":"affected"},{"version":">= 0.22.0, < 0.22.5","status":"affected"}]}],"references":["https://github.com/versatica/mediasoup/security/advisories/GHSA-p7x2-g5cq-fhmq","https://github.com/versatica/mediasoup/pull/1829","https://github.com/versatica/mediasoup/commit/9c1a90a8f9206b965e727d134846fb42df4980a7","https://github.com/versatica/mediasoup/releases/tag/3.20.6"],"weaknesses":["CWE-345"],"ingestedAt":"2026-10-29T20:12:24.861Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/55xxx/CVE-2026-55663.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-55663","state":"PUBLISHED","datePublished":"2026-08-25T18:15:16.059Z","dateUpdated":"2026-08-25T18:55:59.044Z","assignerShortName":"GitHub_M","assignerOrgId":"a0819718-46f1-4df5-94e2-005712e83aaa","dateReserved":"2026-06-17T00:05:03.777Z"},"containers":{"cna":{"title":"mediasoup: SCTP state cookie lacks cryptographic authentication, enabling unauthorized association establishment (RFC 9260 violation)","descriptions":[{"lang":"en","value":"mediasoup is a WebRTC video conferencing system. From version 3.20.0 until 3.20.6 for the npm package and from 0.22.0 until 0.22.5 for the Rust crate, mediasoup's built-in SCTP stack authenticates state cookies using only the hardcoded msworker and 0xAD81 magic values instead of a per-instance secret and HMAC, contrary to RFC 9260 Section 5.1.3. The cookie structure and validation in worker/include/RTC/SCTP/association/StateCookie.hpp and worker/src/RTC/SCTP/association/StateCookie.cpp allow an on-path attacker targeting PlainTransport or PipeTransport with SCTP enabled and without DTLS protection to forge a COOKIE-ECHO whose packet verification tag matches the attacker-controlled localVerificationTag. The forged cookie passes StateCookie::IsMediasoupStateCookie() and Association::HandleReceivedCookieEchoChunk(), establishes an unauthorized SCTP association, and permits DataChannel message injection as a trusted peer. WebRtcTransport is not affected because its SCTP runs inside DTLS. This issue is fixed in npm version 3.20.6 and Rust crate version 0.22.5."}],"affected":[{"vendor":"versatica","product":"mediasoup","versions":[{"version":">= 3.20.0, < 3.20.6","status":"affected"},{"version":">= 0.22.0, < 0.22.5","status":"affected"}]}],"references":[{"url":"https://github.com/versatica/mediasoup/security/advisories/GHSA-p7x2-g5cq-fhmq","name":"https://github.com/versatica/mediasoup/security/advisories/GHSA-p7x2-g5cq-fhmq","tags":["x_refsource_CONFIRM"]},{"url":"https://github.com/versatica/mediasoup/pull/1829","name":"https://github.com/versatica/mediasoup/pull/1829","tags":["x_refsource_MISC"]},{"url":"https://github.com/versatica/mediasoup/commit/9c1a90a8f9206b965e727d134846fb42df4980a7","name":"https://github.com/versatica/mediasoup/commit/9c1a90a8f9206b965e727d134846fb42df4980a7","tags":["x_refsource_MISC"]},{"url":"https://github.com/versatica/mediasoup/releases/tag/3.20.6","name":"https://github.com/versatica/mediasoup/releases/tag/3.20.6","tags":["x_refsource_MISC"]}],"metrics":[{"cvssV3_1":{"attackComplexity":"HIGH","attackVector":"NETWORK","availabilityImpact":"LOW","baseScore":5.6,"baseSeverity":"MEDIUM","confidentialityImpact":"LOW","integrityImpact":"LOW","privilegesRequired":"NONE","scope":"UNCHANGED","userInteraction":"NONE","vectorString":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:L","version":"3.1"}}],"problemTypes":[{"descriptions":[{"cweId":"CWE-345","lang":"en","description":"CWE-345: Insufficient Verification of Data Authenticity","type":"CWE"}]}],"providerMetadata":{"shortName":"GitHub_M","orgId":"a0819718-46f1-4df5-94e2-005712e83aaa","dateUpdated":"2026-08-25T18:15:16.059Z"},"source":{"advisory":"GHSA-p7x2-g5cq-fhmq","discovery":"UNKNOWN"}},"adp":[{"title":"CISA ADP Vulnrichment","references":[{"url":"https://github.com/versatica/mediasoup/security/advisories/GHSA-p7x2-g5cq-fhmq","tags":["exploit"]}],"metrics":[{"other":{"type":"ssvc","content":{"timestamp":"2026-08-25T18:55:43.763697Z","id":"CVE-2026-55663","options":[{"Exploitation":"poc"},{"Automatable":"no"},{"Technical Impact":"partial"}],"role":"CISA Coordinator","version":"2.0.3"}}}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2026-08-25T18:55:59.044Z"}}]}}}