A flaw in the TL‑WR850N v3 router allows cleartext storage of administrative and Wi‑Fi credentials in a region of the device’s flash memory while the serial interface is enabled and protected by weak authentication. The vulnerability, corresponding to CWE‑312, means that an attacker can read the stored credentials directly from flash, thereby learning the router’s management password and wireless network key. These credentials permit full administrative control of the device and unauthorized access to the associated wireless network.

TP‑Link Systems Inc. TL‑WR850N v3 is the sole product identified as affected by this vulnerability. No alternative vendors, products, or firmware versions are listed; thus the issue is confined to routers running the specified firmware version.

The CVSS score of 5.1 indicates moderate severity, but exploitation requires physical access to the router and the ability to connect to its serial port. The serial interface is protected only by weak authentication, so an attacker can connect, read the cleartext credentials from flash, and gain complete administrative control. EPSS data is unavailable and the vulnerability is not included in CISA’s KEV catalog; therefore, while not a widespread or automated threat, it remains a serious risk for physically accessible devices.