CVE-2026-30852: Caddyserver Caddy

High severity, CVSS 7.5. EPSS: 0.5% chance of exploitation in the next 30 days.

Caddy is an extensible server platform that uses TLS by default. From version 2.7.5 to before version 2.11.2, the vars_regexp matcher in vars.go:337 double-expands user-controlled input through the Caddy replacer. When vars_regexp matches against a placeholder like {http.request.header.X-Input}, the header value gets resolved once (expected), then passed through repl.ReplaceAll() again (the bug). This means an attacker can put {env.DATABASE_URL} or {file./etc/passwd} in a request header and the server will evaluate it, leaking environment variables, file contents, and system info. This issue has been patched in version 2.11.2.

Affected products

• Caddyserver Caddy: from 2.7.5, before 2.11.2 (fixed in 2.11.2)

Published 2026-03-07. Last modified 2026-06-17.