Security Advisory on Cleartext Storage of Administrative & Wi-Fi Credentials via Accessible Serial Interface in TP-Link’s TL-WR850N (CVE-2026-4346)

Security Advisory on Cleartext Storage of Administrative & Wi-Fi Credentials via Accessible Serial Interface in TP-Link’s TL-WR850N (CVE-2026-4346)

Vulnerability and Impact Description:

CVE-2026-4346

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.

CVSS v4.0 Score: 5.1 / Medium

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

Affected Products/Versions and Fixes:

Recommendations:

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

1. Download and update to the latest firmware version to fix the vulnerability:

IN: Download for TL-WR850N | TP-Link India

Note: TL-WR850N is not sold in the US.

Disclaimer:

If you do not take all recommended actions, this vulnerability will remain. TP-Link cannot bear any responsibility for consequences that could have been avoided by following this advisory.