ZyXEL P-660HW v3 devices allow remote attackers to cause a denial of service (router unreachable/unresponsive) via a flood of fragmented UDP packets.

ZyXEL P-660HW v3 devices allow remote attackers to cause a denial of service (CPU consumption) via a flood of IP packets with a TTL of 1.

Multiple cross-site scripting (XSS) vulnerabilities in Forms/rpAuth_1 on ZyXEL P-660HW-T1 2 devices with ZyNOS firmware 3.40(AXH.0) allow remote attackers to inject arbitrary web script or HTML via the (1) LoginPassword or (2) hiddenPassword parameter.

Multiple cross-site request forgery (CSRF) vulnerabilities in the Zyxel P-660HW-T1 (v3) wireless router allow remote attackers to hijack the authentication of administrators for requests that change the (1) wifi password or (2) SSID via a request to Forms/WLAN_General_1.

The web management interface on Zyxel P660 devices allows remote attackers to cause a denial of service (reboot) via a flood of TCP SYN packets.

Cross-site scripting (XSS) vulnerability in Allegro RomPager before 4.51, as used on the ZyXEL P660HW-D1, Huawei MT882, Sitecom WL-174, TP-LINK TD-8816, and D-Link DSL-2640R and DSL-2641R, when the "forbidden author header" protection mechanism is bypassed, allows remote attackers to inject arbitrary web script or HTML by requesting a nonexistent URI in conjunction with a crafted HTTP Referer header that is not properly handled in a 404 page. NOTE: there is no CVE for a "URL redirection" issue that some sources list separately.

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 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-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.