CVE-2026-116567highCWE-121

CVE-2026-116567: high-severity vulnerability in signalwire freeswitch

FreeSWITCH: Pre-authentication stack buffer overflow in mod_rtmp control-message handling

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41Vexday Risk Score

No sign of exploitation. It has a public proof of concept.

ssvc Attendcvss 7.5epss 0.4%
from disclosure to weapon4 days
Published on NVDNov 5
1st PoC+4d
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.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Affected products
signalwire · freeswitch
⚠ Public resources, to assess the exposure of systems you control or are authorized to test. Test only with authorization.
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