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CVE-2026-116571— FreeSWITCH: Stack buffer overflow in mod_rtmp AVC sequence-header construction

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，旨在推动电信交换机从专有硬件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，函数在构建 AVC 解码器配置记录时，会将源自网络信道的 SPS 和 PPS 参数值直接复制到固定大小的栈缓冲区中，而未校验其尺寸和帧结构是否适配。若一个已建立的 H.264 呼叫被桥接至 RTMP 端点，攻击者可提供过大的 SPS 和 PPS 参数集，从而导致该函数的栈帧发生溢出。该漏洞仅影响那些编译并加载了模块、并将 RTP 媒体流桥接至 RTMP 分支的部

CVSS 5.9 · Medium Updated Nov 06, 2026

Possible ATT&CK Techniques 3 AI

T1069.004 T1070.001 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: Stack buffer overflow in mod_rtmp AVC sequence-header construction

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_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.

Source: CVE Program / CVE List V5

CVSS Information

CVSS:3.1/AV:N/AC:H/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-2026-116571

#	POC Description	Source Link	Shenlong Link

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III. Intelligence Information for CVE-2026-116571

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Other References for CVE-2026-116571 (3)

https://github.com/signalwire/freeswitch/releases/tag/v1.11.2 x_refsource_MISC
https://github.com/signalwire/freeswitch/security/advisories/GHSA-qmh2-f6cv-79mf x_refsource_CONFIRM
https://github.com/signalwire/freeswitch/commit/2ab0a534fdc25301daf95590e90a756a76bf0950 x_refsource_MISC

https://www.cve.org/CVERecord?id=CVE-2026-116571

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-2026-116567	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-2026-116574	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