Vulnerability · Published Nov 5, 2026 · Assigned by GitHub_M
CVE-2026-116785FreeSWITCH: Pre-authentication heap out-of-bounds write in mod_xml_rpc WebSocket frame length handling
Critical 9.1
In plain English
A critical-severity heap 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 1.0% (higher than 64% 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, ws_read_frame() decoded a WebSocket frame's 64-bit extended payload length with a 32-bit byte swap and narrowed the result into a signed length. A value whose surviving low word became negative bypassed the signed size check and was reinterpreted as an enormous unsigned count, causing client bytes to overwrite memory beyond the 64 KiB receive buffer. Any client completing a /socket WebSocket upgrade on an enabled mod_xml_rpc endpoint reached the parser before HTTP authentication; both the module and WebSocket endpoint are disabled by default. The heap overwrite can corrupt connection pointers and crash FreeSWITCH, ending every concurrent session, although remote 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-122, CWE-681, CWE-787 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:H