The Zyxel P-2602HW-D1A router with 3.40(AJZ.1) firmware maintains authentication state by IP address, which allows remote attackers to bypass authentication by establishing a session from a source IP address of a user who previously authenticated within the previous 5 minutes.

Multiple cross-site request forgery (CSRF) vulnerabilities on the Zyxel P-2602HW-D1A router with 3.40(AJZ.1) firmware allow remote attackers to (1) make the admin web server available on the Internet (WAN) interface via the WWWAccessInterface parameter to Forms/RemMagWWW_1 or (2) change the IP whitelisting timeout via the StdioTimout parameter to Forms/rpSysAdmin_1.

The Zyxel P-2602HW-D1A router with 3.40(AJZ.1) firmware provides different responses to admin page requests depending on whether a user is logged in, which allows remote attackers to obtain current login status by requesting an arbitrary admin URI.