Firmware version 4.60 of Zyxel USG devices contains an undocumented account (zyfwp) with an unchangeable password. The password for this account can be found in cleartext in the firmware. This account can be used by someone to login to the ssh server or web interface with admin privileges.
This vulnerability carries a CRITICAL severity rating with a CVSS v3.1 score of 9.8, indicating it can be exploited remotely over the network with relatively low complexity without requiring user interaction and does not require pre-existing privileges . The vulnerability impacts confidentiality (data exposure), integrity (unauthorized modifications), and availability (service disruption) for affected systems. Impacting 60 products from zyxel, from zyxel, from zyxel and 57 others, organizations running these solutions should prioritize assessment and patching.
Reported in 2020, this vulnerability emerged during an era marked by increased sophistication in supply chain attacks, cloud infrastructure vulnerabilities, and software-as-a-service (SaaS) security challenges. Security practices during this period emphasized zero-trust architectures, container security, and API protection.
2020-12-22T22:15:14.443
2025-11-07T22:03:10.220
Analyzed
CVSSv3.1: 9.8 (CRITICAL)
AV:N/AC:L/Au:N/C:C/I:C/A:C
10.0
10.0
| Type | Vendor | Product | Version/Range | Vulnerable? |
|---|---|---|---|---|
| Operating System | zyxel | usg20-vpn_firmware | 4.60 | Yes |
| Hardware | zyxel | usg20-vpn | - | No |
| Operating System | zyxel | usg20w-vpn_firmware | 4.60 | Yes |
| Hardware | zyxel | usg20w-vpn | - | No |
| Operating System | zyxel | usg40_firmware | 4.60 | Yes |
| Hardware | zyxel | usg40 | - | No |
| Operating System | zyxel | usg40w_firmware | 4.60 | Yes |
| Hardware | zyxel | usg40w | - | No |
| Operating System | zyxel | usg60_firmware | 4.60 | Yes |
| Hardware | zyxel | usg60 | - | No |
| Operating System | zyxel | usg60w_firmware | 4.60 | Yes |
| Hardware | zyxel | usg60w | - | No |
| Operating System | zyxel | usg110_firmware | 4.60 | Yes |
| Hardware | zyxel | usg110 | - | No |
| Operating System | zyxel | usg210_firmware | 4.60 | Yes |
| Hardware | zyxel | usg210 | - | No |
| Operating System | zyxel | usg310_firmware | 4.60 | Yes |
| Hardware | zyxel | usg310 | - | No |
| Operating System | zyxel | usg1100_firmware | 4.60 | Yes |
| Hardware | zyxel | usg1100 | - | No |
| Operating System | zyxel | usg1900_firmware | 4.60 | Yes |
| Hardware | zyxel | usg1900 | - | No |
| Operating System | zyxel | usg2200_firmware | 4.60 | Yes |
| Hardware | zyxel | usg2200 | - | No |
| Operating System | zyxel | zywall110_firmware | 4.60 | Yes |
| Hardware | zyxel | zywall110 | - | No |
| Operating System | zyxel | zywall310_firmware | 4.60 | Yes |
| Hardware | zyxel | zywall310 | - | No |
| Operating System | zyxel | zywall1100_firmware | 4.60 | Yes |
| Hardware | zyxel | zywall1100 | - | No |
| Operating System | zyxel | atp100_firmware | 4.60 | Yes |
| Hardware | zyxel | atp100 | - | No |
| Operating System | zyxel | atp100w_firmware | 4.60 | Yes |
| Hardware | zyxel | atp100w | - | No |
| Operating System | zyxel | atp200_firmware | 4.60 | Yes |
| Hardware | zyxel | atp200 | - | No |
| Operating System | zyxel | atp500_firmware | 4.60 | Yes |
| Hardware | zyxel | atp500 | - | No |
| Operating System | zyxel | atp700_firmware | 4.60 | Yes |
| Hardware | zyxel | atp700 | - | No |
| Operating System | zyxel | atp800_firmware | 4.60 | Yes |
| Hardware | zyxel | atp800 | - | No |
| Operating System | zyxel | vpn50_firmware | 4.60 | Yes |
| Hardware | zyxel | vpn50 | - | No |
| Operating System | zyxel | vpn100_firmware | 4.60 | Yes |
| Hardware | zyxel | vpn100 | - | No |
| Operating System | zyxel | vpn300_firmware | 4.60 | Yes |
| Hardware | zyxel | vpn300 | - | No |
| Operating System | zyxel | vpn1000_firmware | 4.60 | Yes |
| Hardware | zyxel | vpn1000 | - | No |
| Operating System | zyxel | usg_flex_100_firmware | 4.60 | Yes |
| Hardware | zyxel | usg_flex_100 | - | No |
| Operating System | zyxel | usg_flex_100w_firmware | 4.60 | Yes |
| Hardware | zyxel | usg_flex_100w | - | No |
| Operating System | zyxel | usg_flex_200_firmware | 4.60 | Yes |
| Hardware | zyxel | usg_flex_200 | - | No |
| Operating System | zyxel | usg_flex_500_firmware | 4.60 | Yes |
| Hardware | zyxel | usg_flex_500 | - | No |
| Operating System | zyxel | usg_flex_700_firmware | 4.60 | Yes |
| Hardware | zyxel | usg_flex_700 | - | No |
SecUtils normalizes and enriches National Vulnerability Database (NVD) records by standardizing vendor and product identifiers, aggregating vulnerability metadata from both NVD and MITRE sources, and providing structured context for security teams. For zyxel's affected products, we extract Common Platform Enumeration (CPE) data, Common Weakness Enumeration (CWE) classifications, CVSS severity metrics, and reference data to enable rapid vulnerability prioritization and asset correlation. This record contains no exploit code, proof-of-concept instructions, or attack methodologies—only defensive intelligence necessary for patch management, risk assessment, and security operations.