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.

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 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.