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.
Attack Parameters
Attack Vector
Network
Can be exploited remotely
Attack Complexity
Low
Easy to exploit
Attack Requirements
None
No additional conditions
Privileges Required
None
No privileges needed
User Interaction
None
No user interaction needed
Impact Assessment
Confidentiality
None
No data leak
Integrity
Low
Partial data modification
Availability
None
No disruption
CVSS Vector v4.0
Weakness Type (CWE)
Vulnerable Products 1
| Configuration | From (including) | Up to (excluding) |
|---|---|---|
|
Webmin Webmin
cpe:2.3:a:webmin:webmin:*:*:*:*:*:*:*:*
|
— |
2.640
|
References 6
https://github.com/webmin/webmin/releases/tag/2.641
9119a7d8-5eab-497f-8521-727c672e3725
https://raw.githubusercontent.com/cisagov/CSAF/develop/csaf_files/IT/white/2026…
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https://webmin.com/security/#webmin-prior-to-2641
9119a7d8-5eab-497f-8521-727c672e3725
https://www.cve.org/CVERecord?id=CVE-2026-56022
9119a7d8-5eab-497f-8521-727c672e3725
https://github.com/webmin/webmin/releases/tag/2.640
9119a7d8-5eab-497f-8521-727c672e3725
https://webmin.com/security/#webmin-prior-to-2640
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