TLS
CVE-2026-30852
HIGH
GHSA-m2w3-8f23-hxxf
Severity by source
AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
Primary rating from GitHub Advisory.
CVSS VectorGitHub Advisory
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
Lifecycle Timeline
4DescriptionGitHub Advisory
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.
AnalysisAI
Caddy versions 2.7.5 through 2.11.1 contain a template injection vulnerability in the vars_regexp matcher that allows remote attackers to perform double variable expansion on user-controlled input, enabling disclosure of environment variables and file contents. By injecting placeholders like {env.DATABASE_URL} or {file./etc/passwd} into request headers, an unauthenticated attacker can leak sensitive system information. Public exploit code exists for this vulnerability, which is fixed in version 2.11.2.
Technical ContextAI
Affects Caddy. 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
RemediationAI
A vendor patch is available — apply it immediately. Fixed in version 2.11.2.. Restrict network access to the affected service where possible.
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Vendor StatusVendor
SUSE
Severity: High| Product | Status |
|---|---|
| openSUSE Leap 15.6 | Fixed |
| SUSE Linux Enterprise Module for Package Hub 15 SP5 | Fixed |
| SUSE Linux Enterprise Module for Package Hub 15 SP6 | Fixed |
| openSUSE Leap 15.5 | Fixed |
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External POC / Exploit Code
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