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CVE-2026-116785— FreeSWITCH: Pre-authentication heap out-of-bounds write in mod_xml_rpc WebSocket frame length handling

Quick assessment

Affected

signalwire freeswitch

Exploitation

No confirmed in-the-wild exploitation; assess based on exposure

Recommended action

Check the vendor advisory and references for a fixed version. If immediate upgrade is impossible, restrict exposure and increase monitoring.

FreeSWITCH 是一个软件定义电信栈，旨在推动从专有电信交换机向可在任何通用硬件上运行的软件实现进行数字化转型。在 1.11.2 版本之前，ws_read_frame() 函数在解码 WebSocket 帧的 64 位扩展载荷长度时，错误地使用了 32 位字节交换，并将结果截断为有符号长度。若该值的低位字在截断后变为负数，则会绕过有符号长度检查，并被重新解释为一个极大的无符号计数，导致客户端数据溢出 64 KiB 接收缓冲区，覆盖后续内存。任何在已启用 mod_xml_rpc 模块的端点上完成 /socket

CVSS 9.1 · Critical Updated Nov 06, 2026

Possible ATT&CK Techniques 2 AI

T1212 · Exploitation for Credential Access T1190 · Exploit Public-Facing Application

Affected Version Matrix 1

Vendor	Product	Version Range	Status
signalwire	freeswitch	`< 1.11.2`	affected

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Vulnerability Information

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Vulnerability Title

FreeSWITCH: Pre-authentication heap out-of-bounds write in mod_xml_rpc WebSocket frame length handling

Source: CVE Program / CVE List V5

Vulnerability 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.

Source: CVE Program / CVE List V5

CVSS Information

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:H

Source: CVE Program / CVE List V5

Vulnerability Type

堆缓冲区溢出

Source: CVE Program / CVE List V5

Affected Products

Vendor	Product	Affected Versions	CPE	Subscribe
signalwire	freeswitch	< 1.11.2	-

II. Public POCs for CVE-2026-116785

#	POC Description	Source Link	Shenlong Link

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III. Intelligence Information for CVE-2026-116785

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Other References for CVE-2026-116785 (3)

https://github.com/signalwire/freeswitch/releases/tag/v1.11.2 x_refsource_MISC
https://github.com/signalwire/freeswitch/security/advisories/GHSA-jj89-q47c-gh94 x_refsource_CONFIRM
https://github.com/signalwire/freeswitch/commit/d557ca6d29e6da4f10824dc158100906a592b91a x_refsource_MISC

https://www.cve.org/CVERecord?id=CVE-2026-116785

Same Patch Batch · signalwire · 2026-11-05 · 21 CVEs total

CVE-2026-116779	9.8 CRITICAL	FreeSWITCH: Inbound SIP MESSAGE can select the api chat proto and run FreeSWITCH API comma
CVE-2026-116790	9.1 CRITICAL	FreeSWITCH: Inbound ICE connectivity checks are accepted without verifying STUN MESSAGE-IN
CVE-2026-116786	8.8 HIGH	FreeSWITCH: Channel-variable injection via SIP REFER leads to command execution in mod_sof
CVE-2026-116783	8.2 HIGH	FreeSWITCH mod_spandsp: out-of-bounds write parsing UDPTL error-recovery data
CVE-2026-116788	8.2 HIGH	FreeSWITCH: Pre-authentication heap buffer overflow in core XML empty-entity decoding
CVE-2026-116782	7.5 HIGH	FreeSWITCH: Pre-authentication invalid pointer dereference in mod_rtmp connect command han
CVE-2026-116569	7.5 HIGH	FreeSWITCH: Pre-authentication out-of-bounds write in MSRP message body parsing
CVE-2026-116568	7.5 HIGH	FreeSWITCH: Out-of-bounds read in mod_rtmp H.264 video message parsing
CVE-2026-116567	7.5 HIGH	FreeSWITCH: Pre-authentication stack buffer overflow in mod_rtmp control-message handling
CVE-2026-116570	7.5 HIGH	FreeSWITCH: Pre-authentication stack buffer overflow in mod_xml_rpc HTTP directory authent
CVE-2026-116787	7.5 HIGH	FreeSWITCH: Pre-authentication process termination in the Event Socket via an unbounded Co
CVE-2026-115928	7.5 HIGH	FreeSWITCH: Stack buffer overflow parsing the SDP a=crypto key material on inbound calls
CVE-2026-116784	7.5 HIGH	FreeSWITCH: Out-of-bounds read in RTCP NACK feedback parsing
CVE-2026-116789	7.4 HIGH	FreeSWITCH: DTLS-SRTP peer certificate is not bound to the SDP fingerprint when FreeSWITCH
CVE-2026-116572	6.5 MEDIUM	FreeSWITCH mod_sofia: stack buffer overflow from an over-long SIP Contact display-name
CVE-2026-116573	6.5 MEDIUM	FreeSWITCH mod_sofia: stack buffer overflow from an over-long SIP To-header user
CVE-2026-116571	5.9 MEDIUM	FreeSWITCH: Stack buffer overflow in mod_rtmp AVC sequence-header construction
CVE-2026-116574	5.9 MEDIUM	FreeSWITCH: Off-by-one heap write in core XML serialization of four-byte UTF-8 sequences
CVE-2026-116781	5.3 MEDIUM	FreeSWITCH: Pre-authentication out-of-bounds writes in mod_xml_rpc WebSocket frame parsing
CVE-2026-116780	2.7 LOW	FreeSWITCH: Heap out-of-bounds read in FreeSWITCH core variable expansion via `${variable:

IV. Related Vulnerabilities

Same product: freeswitch

Same vendor: signalwire

Same weakness: CWE-122