# CVE-2026-12339: Authenticated Arbitrary File Write Vulnerability in multiple devices

> Authenticated administrators can overwrite arbitrary system files via Zip Slip in the WebUI ISP upgrade, compromising integrity and availability.

- **Severity:** Medium 6.9 (`CVSS:4.0/AV:A/AC:L/AT:N/PR:H/UI:N/VC:N/VI:H/VA:L/SC:N/SI:N/SA:N`)
- **Exploited in the wild:** Not known
- **Login needed:** An administrator
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 10 Aug 2026
- **Updated:** 25 Aug 2026
- **Also known as:** GHSA-www9-662g-pffv

## What is CVE-2026-12339?

CVE-2026-12339 is a medium-severity path traversal vulnerability in TP-Link Systems Inc. Archer MR200 v7, published on 10 Aug 2026. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

A Zip Slip vulnerability in the WebUI ISP
Upgrade functionality allows arbitrary file write via a crafted archive
containing directory traversal sequences. An authenticated administrator may
overwrite arbitrary files on the system.Successful
exploitation may allow arbitrary file to be overwritten on the underlying system, affecting system integrity and availability.

Weakness: CWE-22 (Improper Limitation of a Pathname to a Restricted Directory)

## Which versions are affected by CVE-2026-12339?


## How do I fix CVE-2026-12339?

No fix has been published for CVE-2026-12339 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-12339 being exploited?

There is no known exploitation of CVE-2026-12339 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-12339 and fix it if it is affected.

What it is: CVE-2026-12339 is a medium-severity path traversal vulnerability in TP-Link Systems Inc. Archer MR200 v7, published on 10 Aug 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-12339 in the wild and no public exploit code.

Affected product: TP-Link Systems Inc. Archer MR200 v7. 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-2026-12339/ (Markdown: https://insights.sbomify.com/CVE-2026-12339/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-12339
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-12339
- OSV: https://osv.dev/vulnerability/CVE-2026-12339

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-12339/
Summaries are generated and may contain mistakes; the official description above is the record.