# CVE-2026-4346: Cleartext Storage of Administrative and Wi-Fi Credentials via Accessible Serial Interface in TP Link's TL-WR850N

> Attackers with physical access can extract cleartext admin and Wi-Fi credentials via the serial interface, leading to full device control.

- **Severity:** Medium 5.1 (`CVSS:4.0/AV:P/AC:L/AT:N/PR:H/UI:N/VC:H/VI:N/VA:N/SC:L/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:** 26 Mar 2026
- **Updated:** 27 Mar 2026
- **Also known as:** GHSA-j2f5-7fm8-m5q7

## What is CVE-2026-4346?

CVE-2026-4346 is a medium-severity vulnerability in TP-Link Systems Inc. TL-WR850N v3, published on 26 Mar 2026. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

The vulnerability affecting TL-WR850N v3 allows cleartext storage of administrative and Wi-Fi credentials in a region of the device’s flash memory while the serial interface remains enabled and protected by weak authentication.  An attacker with physical access and the ability to connect to the serial port can recover sensitive information, including the router’s management password and wireless network key.

Successful exploitation can lead to full administrative control of the device and unauthorized access to the associated wireless network.

Weakness: CWE-312 (Cleartext Storage of Sensitive Information)

## Which versions are affected by CVE-2026-4346?

It affects 1 product.


Products: Tp-Link Tl-Wr850n Firmware.

## How do I fix CVE-2026-4346?

No fix has been published for CVE-2026-4346 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-4346 being exploited?

There is no known exploitation of CVE-2026-4346 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-4346 and fix it if it is affected.

What it is: CVE-2026-4346 is a medium-severity vulnerability in TP-Link Systems Inc. TL-WR850N v3, published on 26 Mar 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-2026-4346 in the wild and no public exploit code.

Affected product: TP-Link Systems Inc. TL-WR850N v3. 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-2026-4346/ (Markdown: https://insights.sbomify.com/CVE-2026-4346/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-4346
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-4346
- OSV: https://osv.dev/vulnerability/CVE-2026-4346

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From sbomify Insights: https://insights.sbomify.com/CVE-2026-4346/
Summaries are generated and may contain mistakes; the official description above is the record.