CVE-2026-56022 Webmin CVE debrief

Who should care

Webmin users, administrators of systems using Webmin for management, and security teams responsible for patching and vulnerability management should be aware of this vulnerability.

Technical summary

CVE-2026-56022 is a vulnerability in Webmin that allows for authentication bypass. When an attacker provides the 'User-Agent: webmin' header, Webmin accepts basic authentication without session cookies. This enables attackers to bypass additional MFA requirements. The vulnerability was addressed in Webmin version 2.641. The CVSS vector for this vulnerability is CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X.

Defensive priority

medium

Recommended defensive actions

• Update Webmin to version 2.641 or later
• Review system logs for potential exploitation attempts
• Implement additional security measures such as IP blocking or rate limiting for authentication attempts
• Consider enabling session cookies for Webmin
• Monitor Webmin systems for unusual activity
• Restrict access to Webmin to trusted IP addresses or networks
• Enable MFA for all Webmin users

Evidence notes

The information provided is based on data from the National Vulnerability Database (NVD) and other reliable sources. The CVE record and NVD detail pages provide comprehensive information about this vulnerability.

Official resources