CVE-2022-29402

TP-Link TL-WR840N EU v6.20 was discovered to contain insecure protections for its UART console. This vulnerability allows attackers to connect to the UART port via a serial connection and execute commands as the root user without authentication.

CVE-2021-29280

In TP-Link Wireless N Router WR840N an ARP poisoning attack can cause buffer overflow

CVE-2018-15840

TP-Link TL-WR840N devices allow remote attackers to cause a denial of service (networking outage) via fragmented packets, as demonstrated by an "nmap -f" command.