The TP-LINK TL-WR740N router version 3.12.11 Build 110915 Rel.40896n is vulnerable to multiple HTML injection issues. By inserting HTML code like <h1>Hello<h1> into the Target Description box under Access control settings, an attacker can inject arbitrary HTML code into the webpage.
The exploit allows an unauthenticated user to traverse directories and access sensitive system files like /etc/shadow on TP-Link TL-WR740N version 3.12.11 Build 110915 Rel.40896n. This vulnerability could lead to unauthorized access to critical system information.