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.
Metrics
Affected Vendors & Products
Advisories
| Source | ID | Title |
|---|---|---|
Github GHSA |
GHSA-m2w3-8f23-hxxf | Caddy's vars_regexp double-expands user input, leaking env vars and files |
Fixes
Solution
No solution given by the vendor.
Workaround
No workaround given by the vendor.
References
History
Sat, 07 Mar 2026 16:45:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| 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. | |
| Title | Caddy: vars_regexp double-expands user input, leaking env vars and files | |
| Weaknesses | CWE-200 CWE-74 |
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| References |
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| Metrics |
cvssV4_0
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Projects
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Status: PUBLISHED
Assigner: GitHub_M
Published:
Updated: 2026-03-07T16:28:26.894Z
Reserved: 2026-03-05T21:27:35.341Z
Link: CVE-2026-30852
No data.
Status : Received
Published: 2026-03-07T17:15:52.733
Modified: 2026-03-07T17:15:52.733
Link: CVE-2026-30852
No data.
OpenCVE Enrichment
No data.
Github GHSA