CVE-2026-30852

Name	CVE-2026-30852
Description	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.
Source	CVE (at NVD; CERT, ENISA, LWN, oss-sec, fulldisc, Debian ELTS, Red Hat, Ubuntu, Gentoo, SUSE bugzilla/CVE, GitHub advisories/code/issues, web search, more)

Vulnerable and fixed packages

The table below lists information on source packages.

Source Package	Release	Version	Status
caddy (PTS)	bookworm	2.6.2-5	fixed
	trixie	2.6.2-12	fixed
	sid	2.6.2-14	fixed

The information below is based on the following data on fixed versions.

Package	Type	Release	Fixed Version	Urgency	Origin	Debian Bugs
caddy	source	(unstable)	(not affected)

Notes

- caddy <not-affected> (Vulnerable code introduced later)
https://github.com/caddyserver/caddy/security/advisories/GHSA-m2w3-8f23-hxxf
Introduced with: https://github.com/caddyserver/caddy/commit/85375861f6a903da9af8aa665552a6546d075c9f (v2.7.0-beta.1)