CVSS 4.0
8.5 highCVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:P/VC:H/VI:H/VA:H/SC:N/SI:N/SA:NCVE-2026-125742 7-Zip before 26.06 Heap Out-of-Bounds Write via LZX Decoder in CAB Extraction
High (8.5) in 7-zip 7-zip. EPSS 0.2% estimated probability of exploitation activity in the next 30 days.
On this page
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.
Severity
CVSS 3.1
7.8 highCVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H- EPSS
- 0.2% estimated probability of exploitation activity in the next 30 days; 8th percentile. Scored 2026-11-13. A forecast for this CVE across the internet, not for your own systems.
- CISA's assessment (SSVC)
- Exploitation: PoC · Automatable: no · Technical impact: total, assessed 2026-11-12. From CISA's Vulnrichment in the CVE List: whether it is exploited, whether exploiting it can be automated, and how much control it gives.
- CWE
- CWE-787 Out-of-bounds Write
- Published
- Modified
- Assigned by
- VulnCheck (CNA)
- NVD analysis
- Awaiting analysis
- Record from
- the NVD, synced
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Affected
Versions
From the CNA's record in the CVE List.
| Product | Affected |
|---|---|
| 7-Zip | before 26.06 |
Fix and patched versions
Linux distributions
| Distribution | Release | Package | Fixed in | Advisory |
|---|---|---|---|---|
| Debian | 12 | 7zip, p7zip | no fix listed | DEBIAN-CVE-2026-125742 |
| Debian | 13 | 7zip | no fix listed | DEBIAN-CVE-2026-125742 |
| Debian | 13 | p7zip | 16.02+transitional.1 | DEBIAN-CVE-2026-125742 |
| Debian | 14 | 7zip | 26.06+dfsg-1 | DEBIAN-CVE-2026-125742 |
| Ubuntu | 14.04:LTS, 16.04:LTS, 18.04:LTS and 2 more | p7zip | no fix listed | UBUNTU-CVE-2026-125742 |
| Ubuntu | 26.04:LTS, 26.10, Pro:22.04:LTS and 1 more | 7zip | no fix listed | UBUNTU-CVE-2026-125742 |
From the distributions' data via OSV.dev: the Debian Security Tracker; Ubuntu Security Notices © Canonical Ltd., CC BY-SA 4.0. Modified: reformatted and linked to CVE records. Credits. On the distributions' own pages: Debian · Ubuntu.
References
- https://github.com/ip7z/7zip/blob/26.05/CPP/7zip/Compress/LzxDecoder.cpp#L1496-L1513
- https://github.com/ip7z/7zip/commit/d3296e39e1f1f92c7b41c0c3848e65640428d42d
- https://github.com/ip7z/7zip/releases/tag/26.06
- https://potion-brew.pages.dev/posts/7zip-cab-lzx-window-desync-rce/
- https://www.vulncheck.com/advisories/7-zip-before-26.06-heap-out-of-bounds-write-via-lzx-decoder-in-cab-extraction