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CVE-2026-116567— FreeSWITCH: Pre-authentication stack buffer overflow in mod_rtmp control-message 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堆栈，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，函数在处理 RTMP 用户控制消息时，会使用一个由消息长度（来自网络数据包）控制的无界循环，将消息渲染到一个 200 字节的栈缓冲区中。由于 RTMP 握手过程未对通信双方进行任何身份验证，因此只要消息体长度达到约 70 字节或更多，即可在用户登录前触发栈溢出。该漏洞仅影响已编译并加载模块的部署环境；该模块在默认构建和配置中处于禁用状态，但启用后通常会在 TCP

CVSS 7.5 · High Updated Nov 06, 2026

Possible ATT&CK Techniques 2 AI

T1068.002 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 stack buffer overflow in mod_rtmp control-message 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, 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.

Source: CVE Program / CVE List V5

CVSS Information

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

Source: CVE Program / CVE List V5

Vulnerability Type

栈缓冲区溢出

Source: CVE Program / CVE List V5

Affected Products

Vendor	Product	Affected Versions	CPE	Subscribe
signalwire	freeswitch	< 1.11.2	-

II. Public POCs for CVE-2026-116567

#	POC Description	Source Link	Shenlong Link

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III. Intelligence Information for CVE-2026-116567

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Other References for CVE-2026-116567 (3)

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

https://www.cve.org/CVERecord?id=CVE-2026-116567

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-2026-116785	9.1 CRITICAL	FreeSWITCH: Pre-authentication heap out-of-bounds write in mod_xml_rpc WebSocket frame len
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-2026-116570	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-121