CVE-2026-55663
5.6 · MEDIUMOverview
CVE-2026-55663 is a medium-severity vulnerability. It was published on August 25, 2026 and has a CVSS 3.1 base score of 5.6 (MEDIUM).
This vulnerability has a CVSS 3.1 base score of 5.6, rated MEDIUM. It can be exploited remotely over the network. No authentication or special privileges are required for exploitation.
Technical 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. T
Remediation
Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.
References
Frequently Asked Questions
What is CVE-2026-55663?
CVE-2026-55663 is a medium-severity vulnerability. It was published on August 25, 2026 and has a CVSS 3.1 base score of 5.6 (MEDIUM).
How severe is CVE-2026-55663?
This vulnerability has a CVSS 3.1 base score of 5.6, rated MEDIUM. It can be exploited remotely over the network. No authentication or special privileges are required for exploitation.
How do I fix or remediate CVE-2026-55663?
Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.
How can CyberStrike help with CVE-2026-55663?
CyberStrike's AI-powered security agents can automatically detect CVE-2026-55663 across your infrastructure using autonomous pentesting, DAST scanning, and HackBrowser. The platform continuously monitors for known vulnerabilities and provides actionable remediation guidance prioritized by real-world exploitability.
How CyberStrike Helps
AI agents map your attack surface to find vulnerabilities like this one.
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