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 ISP and Dynamic DNS credentials by sending a direct request for (1) WAN.html, (2) wzPPPOE.html, and (3) rpDyDNS.html, and then reading the HTML source.

ZynOS 3.40 allows remote attackers to cause a denial of service (link restart) by sending a request for the name \M via the SMB Mail Slot Protocol.

ZyXEL Prestige routers, including P-660 and P-661 models with firmware 3.40(AGD.2) through 3.40(AHQ.3), have (1) "user" as their default password for the "user" account and (2) "1234" as their default password for the "admin" account, which makes it easier for remote attackers to obtain access.

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.

Denial of Service via Improper Encoding in Zyxel WRE6505 Web Management Interface

** UNSUPPORTED WHEN ASSIGNED ** An improper encoding or escaping vulnerability in the CGI program of Zyxel WRE6505 v2 firmware version V1.00(ABDV.3)C0 could allow an adjacent attacker on the WLAN to cause a denial-of-service (DoS) condition in the web management interface by convincing an authenticated administrator to visit the “AP Select” page while a malformed SSID is present.

Post-Authentication Command Injection in Zyxel VMG3625‑T50B Firmware

A post-authentication command injection vulnerability in the TR-369 certificate download CGI program of the Zyxel VMG3625-T50B firmware versions through 5.50(ABPM.9.7)C0 could allow an authenticated attacker with administrator privileges to execute operating system (OS) commands on an affected device.

ZyXEL P-335WT router allows remote attackers to bypass access restrictions and conduct unauthorized operations via a UPnP request with a modified InternalClient parameter, which is not validated, as demonstrated by using AddPortMapping to forward arbitrary traffic.

ZyXel P2000W VoIP 802.11b Wireless Phone running firmware WV.00.02 allows remote attackers to obtain sensitive information, such as MAC address and software version, by directly accessing UDP port 9090.

ZyXEL Prestige 623, 650, and 652 HW Routers, and possibly other versions, with HTTP Remote Administration enabled, does not require a password to access rpFWUpload.html, which allows remote attackers to reset the router configuration file.

Zyxel P2000W Version 1 VOIP WIFI Phone Wj.00.10 uses hardcoded IP addresses for its DNS servers, which could allow remote attackers to cause a denial of service or hijack Zyxel phones by attacking or spoofing the hardcoded DNS servers. NOTE: it could be argued that this issue reflects an inherent limitation of DNS itself, so perhaps it should not be included in CVE.

ZyXEL ZyWALL 10 before 3.50 allows remote attackers to cause a denial of service via an ARP packet with the firewall's IP address and an incorrect MAC address, which causes the firewall to disable the LAN interface.

Zyxel P2000W Version 1 VOIP WIFI Phone Wj.00.10 allows remote attackers to obtain sensitive information and possibly cause a denial of service via a direct connection to UDP port 9090, which is undocumented and does not require authentication.

Prestige 650HW-31 running Rompager 4.7 software allows remote attackers to cause a denial of service (device reboot) via a long password.

ZyXEL Prestige 650R-31 router running ZyNOS FW v3.40(KO.1) allows remote attackers to cause a denial of service (CPU consumption and network loss) via crafted fragmented IP packets.

ZyXEL Prestige 642R and 642R-I routers do not filter the routers' Telnet and FTP ports on the external WAN interface from inside access, allowing someone on an internal computer to reconfigure the router, if the password is known.

Zyxel P310, P314, P324 and Netgear RT311, RT314 running the latest firmware, allows remote attackers on the WAN to obtain the IP address of the LAN side interface by pinging a valid LAN IP address, which generates an ARP reply from the WAN address side that maps the LAN IP address to the WAN's MAC address.

ZyXEL Prestige 642R 2.50(FA.1) and Prestige 310 V3.25(M.01), allows remote attackers to cause a denial of service via an oversized, fragmented "jolt" style ICMP packet.

Zyxel Prestige 681 and 1600 SDSL Routers allow remote attackers to cause a denial of service via malformed packets with (1) an IP length less than actual packet size, or (2) fragmented packets whose size exceeds 64 kilobytes after reassembly.

Cross-site scripting (XSS) vulnerability in the web management interface in ZyWALL 10 4.07 allows remote attackers to inject arbitrary web script or HTML via the rpAuth_1 page.

Cross-site scripting (XSS) vulnerability in the Forms/rpSysAdmin script on the Zyxel Prestige 660H-61 ADSL Router running firmware 3.40(PT.0)b32 allows remote attackers to inject arbitrary web script or HTML via hex-encoded values in the a parameter.