CVE-2026-125742 json
7-Zip before 26.06 Heap Out-of-Bounds Write via LZX Decoder in CAB Extraction
published yesterday modified yesterday also EUVD-2026-120897
- cvss
- 7.8
- version 3.1, CNA
- cisa kev
- Not listed
- not in CISA's catalog
- epss
- 0.2%
- EPSS 0.2% chance of exploitation in 30 days, percentile 7%
- public exploits
- 0
- none known
Summary
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.
Patch / fix
- 7-Zip 7-Zip 26.06
- 7zip Debian 14 26.06+dfsg-1
- p7zip Debian 13 16.02+transitional.1
debian advisories DEBIAN-CVE-2026-125742
Is CVE-2026-125742 in your stack? Fencer shows which of your repositories are affected as soon as an advisory lands, and opens the fix as a pull request.
Check with FencerExploit prediction
0.18% chance of exploitation in the next 30 days, higher than 7% of all scored CVEs (FIRST EPSS, 2026-11-11).
Exploits and checks
- potion-brew.pages.dev https://potion-brew.pages.dev/posts/7zip-cab-lzx-window-desync-rce/ referenced PoC, tagged "exploit" by a source, unverified
CVSS scores
| assigned by | version | score | vector |
|---|---|---|---|
| CNA | 4.0 | 8.5 | CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:P/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N |
| CNA | 3.1 | 7.8 | CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H |
| CNA | 4.0 | 8.5 | CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:P/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X |
| NVD | 3.1 | 7.8 | CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H |
Affected products
- 7-Zip 7-Zip
Classification
- Weakness
-
- CWE-787 Out-of-bounds Write
References
-
github.com
/ip7z/7zip/commit/d3296e39e1f1f92c7b41c0c3848e65640428d42d
patch
-
potion-brew.pages.dev
/posts/7zip-cab-lzx-window-desync-rce/
technical-description, exploit
-
github.com
/ip7z/7zip/releases/tag/26.06
release-notes
-
github.com
/ip7z/7zip/blob/26.05/CPP/7zip/Compress/LzxDecoder.cpp#L1496-L1513
product
-
vulncheck.com
/advisories/7-zip-before-26.06-heap-out-of-bounds-write-via-lzx-decoder-in-cab-extraction
third-party-advisory
Sources
- CVE List CVE-2026-125742
- NVD CVE-2026-125742
Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.