P7zip: 7-Zip before 26.06 contains a heap out-of-bounds write vulnerability in the LZX decoder that lets attackers
Affects p7zipSource GCVE Database
Not known to be exploited · CVSS 8.5 High.
Data as of 13 Nov 2026, 22:31 UTC
Thin evidence
One scorer or none| CNA (VulnCheck) | CVSS 4.0 | 8.5 |
|---|---|---|
| CNA (VulnCheck) | CVSS 3.1 | 7.8 |
CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:P/VC:H/VI:H/VA:H/SC:N/SI:N/SA:NExploitation evidence
Disclosed: evidence found.
CVE published 10 Nov 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 13 Nov 2026.
What to do
Affected software
| Product | Affected | Fixed in |
|---|---|---|
Ubuntu 26.107zippkg:deb/ubuntu/7zip?arch=source&distro=stonkingOther threats | Affected
| Fixed in– |
Ubuntu 26.04 LTS7zippkg:deb/ubuntu/7zip?arch=source&distro=resoluteOther threats | Affected
| Fixed in– |
Ubuntu Pro 24.04 LTS7zippkg:deb/ubuntu/7zip?arch=source&distro=esm-apps/nobleOther threats | Affected
| Fixed in– |
Ubuntu 22.04 LTSp7zippkg:deb/ubuntu/p7zip?arch=source&distro=jammyOther threats | Affected
| Fixed in– |
Ubuntu Pro 22.04 LTS7zippkg:deb/ubuntu/7zip?arch=source&distro=esm-apps/jammyOther threats | Affected
| Fixed in– |
Ubuntu 20.04 LTSp7zippkg:deb/ubuntu/p7zip?arch=source&distro=focalOther threats | Affected
| Fixed in– |
Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.
AI-suggested
Until a fix is applied, users should avoid extracting untrusted multi-volume CAB archives to mitigate risk.
Description
A heap out-of-bounds write vulnerability exists in the LZX decoder of 7-Zip versions before 26.06. This flaw allows attackers to corrupt memory by crafting multi-volume CAB archives with a smaller window declaration, leading to a stale _pos value that bypasses bounds checks. Exploitation can result in arbitrary code execution when victims extract these malicious archives.
References
- ubuntu.com/security/CVE-2026-125742 (opens in a new tab)
- cve.org/CVERecord?id=CVE-2026-125742 (opens in a new tab)
- github.com/ip7z/7zip/commit/d3296e39e1f1f92c7b41c0c3848e65640428d42d (opens in a new tab)
- github.com/ip7z/7zip/blob/26.05/CPP/7zip/Compress/LzxDecoder.cpp (opens in a new tab)
- github.com/ip7z/7zip/releases/tag/26.06 (opens in a new tab)
- potion-brew.pages.dev/posts/7zip-cab-lzx-window-desync-rce/ (opens in a new tab)
- vulncheck.com/advisories/7-zip-before-26.06-heap-out-of-bounds-write-via-lzx-decoder-in-cab-extraction (opens in a new tab)