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.
Published: 2026-08-25
Score: 5.6 Medium
EPSS: n/a
KEV: No
Impact: n/a
Action: n/a
AI Analysis

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Remediation

No vendor fix or workaround currently provided.

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Tracking

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Advisories
Source ID Title
Github GHSA Github GHSA GHSA-p7x2-g5cq-fhmq mediasoup: SCTP state cookie lacks cryptographic authentication, enabling unauthorized association establishment (RFC 9260 violation)
History

Tue, 25 Aug 2026 19:30:00 +0000

Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'poc', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

Tue, 25 Aug 2026 18:30:00 +0000

Type Values Removed Values Added
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.
Title mediasoup: SCTP state cookie lacks cryptographic authentication, enabling unauthorized association establishment (RFC 9260 violation)
Weaknesses CWE-345
References
Metrics cvssV3_1

{'score': 5.6, 'vector': 'CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:L'}

Subscriptions

No data.

cve-icon MITRE

Status: PUBLISHED

Assigner: GitHub_M

Published:

Updated: 2026-08-25T18:55:59.044Z

Reserved: 2026-06-17T00:05:03.777Z

Link: CVE-2026-55663

cve-icon Vulnrichment

Updated: 2026-08-25T18:55:52.575Z

cve-icon NVD

Status : Received

Published: 2026-08-25T19:16:51.060

Modified: 2026-08-25T19:16:51.060

Link: CVE-2026-55663

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

No data.

Weaknesses
  • CWE-345

    Insufficient Verification of Data Authenticity