CVE-2026-30852

HIGH

7.5

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.

CVE Details

CVSS v3.1 Score7.5

SeverityHIGH

CVSS VectorCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N

Attack VectorNETWORK

ComplexityLOW

Privileges RequiredNONE

User InteractionNONE

Published3/7/2026

Last Modified3/11/2026

Sourcenvd

Honeypot Sightings0

Affected Products

caddyserver:caddy

Weaknesses (CWE)

CWE-74CWE-200

References

https://github.com/caddyserver/caddy/pull/5408(security-advisories@github.com)

https://github.com/caddyserver/caddy/releases/tag/v2.11.2(security-advisories@github.com)

https://github.com/caddyserver/caddy/security/advisories/GHSA-m2w3-8f23-hxxf(security-advisories@github.com)

IOC Correlations

No correlations recorded

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