ZyXEL Prestige routers, including P-660 and P-661 models with firmware 3.40(AGD.2) through 3.40(AHQ.3), allow remote authenticated users to gain privileges by accessing administrative URIs, as demonstrated by rpSysAdmin.html.

ZyXEL Prestige routers, including P-660, P-661, and P-662 models with firmware 3.40(PE9) and 3.40(AGD.2) through 3.40(AHQ.3), do not use a salt when calculating an MD5 password hash, which makes it easier for attackers to crack passwords.

The default SNMP configuration on ZyXEL Prestige routers, including P-660 and P-661 models with firmware 3.40(AGD.2) through 3.40(AHQ.3), has a Trusted Host value of 0.0.0.0, which allows remote attackers to send SNMP requests from any source IP address.

ZyXEL Prestige routers, including P-660, P-661, and P-662 models with firmware 3.40(AGD.2) through 3.40(AHQ.3), allow remote authenticated users to obtain authentication data by making direct HTTP requests and then reading the HTML source, as demonstrated by a request for (1) RemMagSNMP.html, which discloses SNMP communities; or (2) WLAN.html, which discloses WEP keys.

ZyXEL ZyWALL 1050 has a hard-coded password for the Quagga and Zebra processes that is not changed when it is set by a user, which allows remote attackers to gain privileges.

The ZyXEL P-660HW series router has "admin" as its default password, which allows remote attackers to gain administrative access.

Cross-site scripting (XSS) vulnerability in Forms/DiagGeneral_2 on the ZyXEL P-660HW series router allows remote attackers to inject arbitrary web script or HTML via the PingIPAddr parameter.

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.

The ZyXEL P-660HW series router maintains authentication state by IP address, which allows remote attackers to bypass authentication by establishing a session from a source IP address of a previously authenticated user.

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.