Elixir WebRTC’s DTLS client (active) handshake fails to verify the peer’s certificate fingerprint, removing one half of WebRTC’s mutual authentication. While this flaw alone does not allow media interception in standard deployments, it enables a full man-in-the-middle compromise when combined with insecure signalling or a peer that shares similar validation gaps. The vulnerability therefore undermines confidentiality and trust of WebRTC communications.

The issue affects the elixir-webrtc ex_webrtc library in any release prior to version 0.15.1 and before 0.16.1. No other products or vendor versions are listed as impacted.

A CVSS score of 8.7 indicates a high severity risk. The EPSS score is not available, and the vulnerability is not listed in CISA’s KEV catalog. The likely attack vector requires an attacker who can participate in the DTLS handshake and also control or tamper with the signalling channel, such as through a malicious relay or by compromising a signalling peer. Under those conditions the attacker can intercept or alter media streams by posing as either side of the connection.