Vulnerability · Published Jun 18, 2026 · Assigned by cisa-cg
CVE-2026-56020Webmin HTTP header authentication bypass
High 8.1
In plain English
A high-severity authentication bypass by spoofing in Webmin from Webmin. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.5% (higher than 43% of all known vulnerabilities).
Severity (CVSS 3.1)8.1High
Exploit odds (30 days)0.5%top 57.3% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack toolingNoneno public tooling known
Official 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.
Affected products (as reported)
Weakness: CWE-290 · Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H