CVE-2026-116789
FreeSWITCH: DTLS-SRTP peer certificate is not bound to the SDP fingerprint when FreeSWITCH is the DTLS server
FreeSWITCH is a Software Defined Telecom Stack enabling the digital transformation from proprietary telecom switches to a software implementation that runs on any commodity hardware. Prior to 1.11.2, dtls_state_setup() compared a peer certificate with the SDP a=fingerprint only when FreeSWITCH was the DTLS client, not when it held the DTLS server role. An unauthenticated peer able to reach the negotiated media port could complete the DTLS-SRTP handshake with an unrelated certificate, obtain the leg's SRTP keys, decrypt and inject media, and displace the legitimate endpoint; on ICE-enabled legs the peer also needs the connectivity-check credentials from SDP, which generally requires signaling visibility or a position on its path. WebRTC and SIP DTLS-SRTP legs are affected whenever the peer selects the active role, while FreeSWITCH client-role handshakes already perform fingerprint validation. Version 1.11.2 introduces the remediation, which requires rtp_dtls_client_cert_verify_mode=fingerprint.
| CWE | CWE-295 CWE-300 |
| Vendor | signalwire |
| Product | freeswitch |
| Published | Nov 5, 2026 |
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CVSS v3 Breakdown
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N