SignalWire FreeSWITCH up to 1.11.1 DTLS-SRTP Handshake dtls_state_setup certificate validation

Summaryinfo

A vulnerability classified as problematic has been found in SignalWire FreeSWITCH up to 1.11.1. The impacted element is the function dtls_state_setup of the component DTLS-SRTP Handshake. This manipulation causes certificate validation. This vulnerability is tracked as CVE-2026-116789. The attack is possible to be carried out remotely. No exploit exists. It is recommended to upgrade the affected component.

Detailsinfo

A vulnerability was found in SignalWire FreeSWITCH up to 1.11.1. It has been declared as problematic. Affected by this vulnerability is the function dtls_state_setup of the component DTLS-SRTP Handshake. The manipulation with an unknown input leads to a certificate validation vulnerability. The CWE definition for the vulnerability is CWE-295. The product does not validate, or incorrectly validates, a certificate. As an impact it is known to affect integrity. The summary by CVE is:

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.

It is possible to read the advisory at github.com. This vulnerability is known as CVE-2026-116789 since 10/26/2026. The exploitation appears to be difficult. The attack can be launched remotely. The exploitation doesn't need any form of authentication. Technical details of the vulnerability are known, but there is no available exploit. The attack technique deployed by this issue is T1587.003 according to MITRE ATT&CK.

Upgrading to version 1.11.2 eliminates this vulnerability.

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Productinfo

Vendor

• SignalWire

Name

• FreeSWITCH

Version

• 1.11.0
• 1.11.1

Website

• Product: https://github.com/signalwire/freeswitch/

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