In the web server on D-Link DIR-620 devices with a certain customized (by ISP) variant of firmware 1.0.3, 1.0.37, 1.3.1, 1.3.3, 1.3.7, 1.4.0, and 2.0.22, there is a hardcoded password of anonymous for the admin account.
https://www.bleepingcomputer.com/news/security/backdoor-account-found-in-d-link-dir-620-routers/
https://securityaffairs.co/wordpress/72839/hacking/d-link-dir-620-flaws.html
http://www.securitynewspaper.com/2018/05/25/d-link-dir-620-routers-critical-vulnerabilities/
https://securelist.com/backdoors-in-d-links-backyard/85530/
Source: Mitre, NVD
Published: 2018-06-20
Updated: 2026-06-17
Base Score: 10
Vector: CVSS2#AV:N/AC:L/Au:N/C:C/I:C/A:C
Severity: Critical
Base Score: 9.8
Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
EPSS: 0.03278