CVE-2026-125742— 7-Zip before 26.06 Heap Out-of-Bounds Write via LZX Decoder in CAB Extraction

Quick assessment

Affected

7-Zip 7-Zip

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.

7-Zip 26.06 之前的版本中，LZX 解码器存在一个堆缓冲区溢出（越界写入）漏洞。当连续的多卷 CAB 压缩包声明的窗口尺寸较小时，攻击者可利用此漏洞破坏内存。攻击者可以诱导受害者解压特制的多卷 CAB 档案，其中过时的值会绕过边界检查，从而导致任意代码执行。

CVSS 7.8 · High Updated Nov 10, 2026

Possible ATT&CK Techniques 2 AI

T1059 · Command and Scripting Interpreter T1190 · Exploit Public-Facing Application

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Vulnerability Information

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Vulnerability Title

7-Zip before 26.06 Heap Out-of-Bounds Write via LZX Decoder in CAB Extraction

Source: CVE Program / CVE List V5

Vulnerability Description

7-Zip before 26.06 contains a heap out-of-bounds write vulnerability in the LZX decoder that lets attackers corrupt memory when a continuation CAB volume declares a smaller window. Attackers can entice victims to extract crafted multi-volume CAB archives, where a stale _pos value bypasses bounds checks, enabling arbitrary code execution.

Source: CVE Program / CVE List V5

CVSS Information

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

Source: CVE Program / CVE List V5

Vulnerability Type

跨界内存写

Source: CVE Program / CVE List V5

Affected Products

Vendor	Product	Affected Versions	CPE	Subscribe
7-Zip	7-Zip	0 ~ 26.06	-

II. Public POCs for CVE-2026-125742

#	POC Description	Source Link	Shenlong Link

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III. Intelligence Information for CVE-2026-125742

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Other References for CVE-2026-125742 (5)

https://github.com/ip7z/7zip/blob/26.05/CPP/7zip/Compress/LzxDecoder.cpp#L1496-L1513 product
https://github.com/ip7z/7zip/commit/d3296e39e1f1f92c7b41c0c3848e65640428d42d patch
https://potion-brew.pages.dev/posts/7zip-cab-lzx-window-desync-rce/ technical-description exploit
https://github.com/ip7z/7zip/releases/tag/26.06 release-notes
https://www.vulncheck.com/advisories/7-zip-before-26.06-heap-out-of-bounds-write-via-lzx-decoder-in-cab-extraction third-party-advisory

https://www.cve.org/CVERecord?id=CVE-2026-125742

IV. Related Vulnerabilities

Same product: 7-Zip

Same vendor: 7-Zip

Same weakness: CWE-787