What’s Vulnerable › Vulnerabilities

CVE-2026-56022: Webmin MFA bypass

• Severity: medium (CVSS 5.3 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.6% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-06-18 · updated 2026-08-11
• Weakness: CWE-308

Description

Webmin accepts basic authentication without session cookies when an attacker provides the 'User-Agent: webmin' header, allowing bypass of additional MFA requirements. Fixed in 2.640.

Affected products

• Webmin: before 2.640 — fixed in 2.640

How to fix

Upgrade to a fixed version: Webmin 2.640. Check the vendor advisory for mitigations.

References

• https://github.com/webmin/webmin/releases/tag/2.640
• https://raw.githubusercontent.com/cisagov/CSAF/develop/csaf_files/IT/white/2026/va-26-169-02.json
• https://webmin.com/security/#webmin-prior-to-2640
• https://www.cve.org/CVERecord?id=CVE-2026-56022

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