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.
Published: 2026-02-24
CVSS: 9.1
CVSS Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
Download CVE-2026-27588 POC (Proof-of-Concept) here:
Tip: Download official Tor Browser at https://www.torproject.org/download/ to access .onion links.
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https://dnacompany.com/poc-236-cve-2026-25875/