cvedb.io
CVE-2026-27588
CRITICAL · CVSS 9.1
EPSS exploitation probability: 0%
Published 2026-02-24T17:29:04.163 · Last modified 2026-06-17T10:27:21.117

Summary

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.

Affected products

caddyserver — caddy

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References

This product uses data from the NVD API but is not endorsed or certified by the NVD. Informational only; not professional security advice.