CVE-2026-30852 (GCVE-0-2026-30852)
Vulnerability from cvelistv5 – Published: 2026-03-07 16:28 – Updated: 2026-03-07 16:28
VLAI?
Title
Caddy: vars_regexp double-expands user input, leaking env vars and files
Summary
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.
Severity ?
CWE
Assigner
References
| URL | Tags | ||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
|
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Impacted products
| Vendor | Product | Version | ||
|---|---|---|---|---|
| caddyserver | caddy |
Affected:
>= 2.7.5, < 2.11.2
|
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}
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"privilegesRequired": "NONE",
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"subIntegrityImpact": "NONE",
"userInteraction": "NONE",
"vectorString": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N/E:P",
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},
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"tags": [
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},
{
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"source": {
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"discovery": "UNKNOWN"
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"title": "Caddy: vars_regexp double-expands user input, leaking env vars and files"
}
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"datePublished": "2026-03-07T16:28:26.894Z",
"dateReserved": "2026-03-05T21:27:35.341Z",
"dateUpdated": "2026-03-07T16:28:26.894Z",
"state": "PUBLISHED"
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}
}
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Sightings
| Author | Source | Type | Date |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or observed by the user.
- Confirmed: The vulnerability has been validated from an analyst's perspective.
- Published Proof of Concept: A public proof of concept is available for this vulnerability.
- Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
- Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
- Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
- Not confirmed: The user expressed doubt about the validity of the vulnerability.
- Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.
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