Vulnerability · Published Nov 5, 2026 · Assigned by GitHub_M
CVE-2026-116571FreeSWITCH: Stack buffer overflow in mod_rtmp AVC sequence-header construction
Medium 5.9
In plain English
A medium-severity stack buffer overflow in freeswitch from signalwire. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.4% (higher than 31% of all known vulnerabilities).
Official 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_rtp2rtmpH264() built an AVC decoder configuration record in a fixed stack buffer by copying wire-derived SPS and PPS values without checking that their sizes and framing fit. An established H.264 call bridged toward an RTMP endpoint could supply oversized SPS and PPS parameter sets and overrun the function's stack frame. The flaw affects only deployments that build and load mod_rtmp and bridge RTP media into an RTMP leg; the module is disabled in the stock build and configuration. The corruption can abort FreeSWITCH and terminate every active call, and builds without stack protection receive a limited stack-write primitive, although code execution has not been demonstrated. This issue is fixed in version 1.11.2.
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| signalwire | freeswitch | < 1.11.2 |
Weakness: CWE-121 · Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H