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CVE-2026-56021 Webmin CVE debrief

CVE-2026-56021 is a medium-severity vulnerability in Webmin that allows unauthenticated attackers to read .conf files within module directories. This issue arises from a bypassable regex pattern. The vulnerability has a CVSS score of 6.9 and is considered medium severity. Webmin users should be aware of this issue and take necessary actions to mitigate it. The CVE was published on June 18, 2026, and no modifications have been made since then. There is no known ransomware campaign use associated with this vulnerability. Users can find more information and potential fixes through the provided resource links.

Vendor
Webmin
Product
Unknown
CVSS
MEDIUM 6.9
CISA KEV
Not listed in stored evidence
Original CVE published
2026-06-18
Original CVE updated
2026-06-22
Advisory published
2026-06-18
Advisory updated
2026-06-22

Who should care

Webmin users, administrators, and security teams should be aware of this vulnerability and take necessary actions to mitigate it. This includes reviewing Webmin configurations, updating to the latest version if available, and monitoring for potential exploitation attempts.

Technical summary

The vulnerability CVE-2026-56021 in Webmin allows unauthenticated attackers to read the contents of any file ending in .conf within module directories. This is due to a bypassable regex pattern used in the application. The CVSS score for this vulnerability is 6.9, indicating medium severity. The vulnerability was published on June 18, 2026, and has not been modified since. The CVSS vector is CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:N/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 the latest version if available.
  • Review Webmin configurations to ensure they are secure.
  • Monitor for potential exploitation attempts.
  • Restrict access to Webmin module directories.
  • Implement additional security measures such as Web Application Firewalls (WAFs).
  • Regularly review and update security patches for Webmin.

Evidence notes

The information provided is based on the CVE record and NVD details. The CVE was published on June 18, 2026, and no modifications have been made since then. The vulnerability has a CVSS score of 6.9 and is considered medium severity. The regex pattern used in Webmin can be bypassed, allowing unauthenticated file reads.

Official resources

public