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


- **Severity:** High 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`)
- **Exploited in the wild:** Not known
- **Fix available:** Yes
- **Published:** 10 Nov 2026
- **Updated:** 12 Nov 2026
- **Also known as:** DEBIAN-CVE-2026-125742, ECHO-4241-5225-d183, GHSA-vfpw-mfgh-fqwf, UBUNTU-CVE-2026-125742

## What is CVE-2026-125742?

CVE-2026-125742 is a high-severity vulnerability in 7-Zip, published on 10 Nov 2026. 

### Official 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.

Weakness: CWE-787 (Out-of-bounds Write)

## Which versions are affected by CVE-2026-125742?


## How do I fix CVE-2026-125742?

Upgrade to a fixed version.

## Is CVE-2026-125742 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-125742 exists.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-125742 and fix it if it is affected.

What it is: CVE-2026-125742 is a high-severity vulnerability in 7-Zip, published on 10 Nov 2026. 
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-125742 exists.

Affected product: 7-Zip. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-125742/ (Markdown: https://insights.sbomify.com/CVE-2026-125742/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-125742
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-125742
- OSV: https://osv.dev/vulnerability/CVE-2026-125742

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-125742/
Summaries are generated and may contain mistakes; the official description above is the record.