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Vulnerability record · CVE-2026-56020 · published 18 June 2026

CVE-2026-56020: Authentication bypass by spoofing vulnerability

The Webmin HTTP server (miniserv.pl) allows unauthenticated attackers to impersonate any user with a configured SSL client certificate by sending a forged HTTP header. A remote attacker can spoof certificate DNs and authenticate as any user. Fixed in 2.202.

9.2 CVSS 4.0 Critical EPSS 0.50% · top 60.0% CWE-290 · Authentication bypass by spoofing Awaiting Analysis
9.2CVSS 4.0 base score
0.50%EPSS exploitation probability, 30 days
NoNot in CISA KEV
0Affected product versions listed by NVD
4References
11 Aug 2026Last modified by NVD

Description

The Webmin HTTP server (miniserv.pl) allows unauthenticated attackers to impersonate any user with a configured SSL client certificate by sending a forged HTTP header. A remote attacker can spoof certificate DNs and authenticate as any user. Fixed in 2.202.

CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:H/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:

References

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Related vulnerabilities

Same products first, then exploited flaws of the same weakness class.

Source: NIST National Vulnerability Database (record CVE-2026-56020), CISA KEV, FIRST EPSS (scores of 2026-09-27). This page is refreshed as NVD updates the record.