CVE-2026-27587: Caddyserver Caddy

Critical severity, CVSS 9.1. EPSS: 0.5% chance of exploitation in the next 30 days.

Caddy is an extensible server platform that uses TLS by default. Prior to version 2.11.1, Caddy's HTTP `path` request matcher is intended to be case-insensitive, but when the match pattern contains percent-escape sequences (`%xx`) it compares against the request's escaped path without lowercasing. An attacker can bypass path-based routing and any access controls attached to that route by changing the casing of the request path. Version 2.11.1 contains a fix for the issue.

Affected products

• Caddyserver Caddy: from 2.10.2, before 2.11.1 (fixed in 2.11.1)

Published 2026-02-24. Last modified 2026-06-17.