FreeSWITCH is a Software Defined Telecom Stack enabling the digital transformation from proprietary…

Why it is Yellow

• CVSS 7.5 high
• Remotely exploitable without logging in

References

• https://github.com/signalwire/freeswitch/commit/fc0db829b87d1a5a3043e355b4294c41851b13c6
• https://github.com/signalwire/freeswitch/releases/tag/v1.11.2
• https://github.com/signalwire/freeswitch/security/advisories/GHSA-hj6x-9653-p796

Original description

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, rtmp_handle_control() rendered an RTMP user-control message into a 200-byte stack buffer using an unbounded sprintf loop controlled by the wire message length. A body of roughly 70 bytes or more overflowed the stack before any RTMP login, because the handshake authenticates neither side. The flaw affects deployments that build and load mod_rtmp, which is disabled in the stock build and configuration but commonly exposes a listener on TCP port 1935 when enabled. One unauthenticated message can crash FreeSWITCH and end every active call; the constrained ASCII hex output has not yielded control-flow hijacking. This issue is fixed in version 1.11.2.