CVE-2026-27588 — Caddy: MatchHost becomes case-sensitive for large host lists (>100), enabling host-based route/auth bypass
Caddy is an extensible server platform that uses TLS by default. Prior to version 2.11.1, Caddy's HTTP `host` request matcher is documented as case-insensitive, but when configu…
Published: 2026-02-24 · CVSS: 7.7 · CVSS 4.0
Caddy is an extensible server platform that uses TLS by default. Prior to version 2.11.1, Caddy's HTTP `host` request matcher is documented as case-insensitive, but when configured with a large host list (>100 entries) it becomes case-sensitive due to an optimized matching path. An attacker can bypass host-based routing and any access controls attached to that route by changing the casing of the `Host` header. Version 2.11.1 contains a fix for the issue.
Source: CVE Program · Revision 8b16575c39f1e1810c5e863010da073d2d3285e7