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CVE-2026-116574— FreeSWITCH: Off-by-one heap write in core XML serialization of four-byte UTF-8 sequences

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运行在任何通用硬件上的软件实现进行数字化转型。在 1.11.2 版本之前，switch_xml_ampencode() 函数仅为由四字节 UTF-8 序列生成的最宽数字字符引用预留了 10 个字节，却未为终止的空字符（NUL）预留空间。当远程提供的文本在缓冲区增长边界处被序列化时，终止符会向堆分配区域之外写入一个字节。受影响的接口包括 mod_xml_cdr、会议模块、格式化 CDR XML、XML 事件套接字输出以及序列化由调用方控制值的 X

CVSS 5.9 · Medium

Possible ATT&CK Techniques 1 AI

T1190 · Exploit Public-Facing Application

Affected Version Matrix 1

VendorProduct Version RangeStatus
signalwire freeswitch < 1.11.2 affected
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I. Basic Information for CVE-2026-116574

Vulnerability Information
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Vulnerability Title
FreeSWITCH: Off-by-one heap write in core XML serialization of four-byte UTF-8 sequences
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, switch_xml_ampencode() reserved only ten bytes for the widest numeric character reference produced from a four-byte UTF-8 sequence, omitting space for the terminating NUL. When remote-supplied text was serialized at the exact buffer-growth boundary, the terminator wrote one byte beyond the heap allocation. Reachable surfaces include mod_xml_cdr, conference and formatted CDR XML, XML Event Socket output, and XML API output that serializes caller-controlled values. The fixed zero-byte write can abort the process or truncate an adjacent object, while 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:H/PR:L/UI:N/S:U/C:N/I:L/A:H
Source: CVE Program / CVE List V5
Vulnerability Type
Off-by-one错误
Source: CVE Program / CVE List V5

Affected Products

Vendor Product Affected Versions CPE Subscribe
signalwire freeswitch < 1.11.2 -

II. Public POCs for CVE-2026-116574

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III. Intelligence Information for CVE-2026-116574

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Other References for CVE-2026-116574 (3)

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-2026-116785 9.1 CRITICAL FreeSWITCH: Pre-authentication heap out-of-bounds write in mod_xml_rpc WebSocket frame len
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-2026-116569 7.5 HIGH FreeSWITCH: Pre-authentication out-of-bounds write in MSRP message body parsing
CVE-2026-116782 7.5 HIGH FreeSWITCH: Pre-authentication invalid pointer dereference in mod_rtmp connect command han
CVE-2026-116784 7.5 HIGH FreeSWITCH: Out-of-bounds read in RTCP NACK feedback parsing
CVE-2026-115928 7.5 HIGH FreeSWITCH: Stack buffer overflow parsing the SDP a=crypto key material on inbound calls
CVE-2026-116787 7.5 HIGH FreeSWITCH: Pre-authentication process termination in the Event Socket via an unbounded Co
CVE-2026-116570 7.5 HIGH FreeSWITCH: Pre-authentication stack buffer overflow in mod_xml_rpc HTTP directory authent
CVE-2026-116567 7.5 HIGH FreeSWITCH: Pre-authentication stack buffer overflow in mod_rtmp control-message handling
CVE-2026-116568 7.5 HIGH FreeSWITCH: Out-of-bounds read in mod_rtmp H.264 video message 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-2026-116781 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-193