Security Advisory: Authenticated Arbitrary File Write vulnerability in multiple devices (CVE-2026-12339)

Security Advisory: Authenticated Arbitrary File Write vulnerability in multiple devices (CVE-2026-12339)

Vulnerability and Impact Description:

CVE-2026-12339

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 overwrite on the underlying system, potentially affecting system integrity and availability.

CVSS v4.0 Score: 6.9 /Medium

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

Affected Products/Versions and Fixes:

Recommendations:

We strongly recommend that users with affected devices take the following actions:

1. Update affected devices to the latest firmware version that fixed the vulnerability:

EN: Download for TL-MR6400 | TP-Link

Download for Archer MR600 | TP-Link

Download for Archer MR200 | TP-Link

Note: TL-MR6400, Archer MR600, and Archer MR200 are not sold in the US.

Disclaimer:

This advisory is provided for informational purposes only and is subject to change without notice. The information is provided “as is” without warranties of any kind. TP-Link recommends that customers promptly apply available firmware updates or implement documented workarounds as provided in this advisory. Devices/systems that are not updated or mitigated as described may remain vulnerable, and TP-Link disclaims any responsibility or liability for any damages or losses arising from a failure to implement such updates.