Bug 2567802 (CVE-2026-116789)

Summary: CVE-2026-116789 freeswitch: FreeSWITCH: Media session interception via missing DTLS certificate fingerprint validation
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
Status: NEW --- QA Contact:
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Priority: high    
Version: unspecifiedKeywords: Security
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Hardware: All   
OS: Linux   
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A flaw was found in FreeSWITCH. When operating as a Datagram Transport Layer Security (DTLS) server, the service fails to validate peer certificates against the expected Session Description Protocol (SDP) fingerprint. An unauthenticated remote attacker capable of reaching the negotiated media port can complete a handshake using an arbitrary certificate to capture encryption keys. This allows the attacker to decrypt sensitive media streams, inject unauthorized audio or video, and displace legitimate callers.
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Description OSIDB Bzimport 2026-11-05 22:27:12 UTC 
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.