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CVE-2026-30852

Caddyserver Caddy injection

7.5 HIGHPublic exploitEPSS 0.51%
  1. Published7 Mar 2026

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.

CVSS 3.1 breakdown

Attack vectorNetwork
Attack complexityLow
Privileges requiredNone
User interactionNone
ScopeUnchanged
ConfidentialityHigh
IntegrityNone
AvailabilityNone
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N

Affected products

Caddyserver Caddy≥ 2.7.5 < 2.11.2

Remediation

Fixed in
Caddyserver Caddy≥ 2.11.2

References

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Frequently asked

Is CVE-2026-30852 being actively exploited?

CVE-2026-30852 is not in the CISA KEV catalog. A public exploit reference exists, so treat it as exploitable. Its EPSS exploit probability is 0.51%.

How severe is CVE-2026-30852?

CVE-2026-30852 has a CVSS 3.1 base score of 7.5, rated high. EPSS estimates a 0.51% probability of exploitation.

Which products are affected by CVE-2026-30852?

Affected products include Caddyserver Caddy.

How do I fix CVE-2026-30852?

Upgrade affected software to a fixed version, for example Caddyserver Caddy 2.11.2 or later, then confirm no affected versions remain in your inventory.

How Secuno handles this

Secuno correlates vulnerabilities like CVE-2026-30852 against the real software inventory on every managed device, as each hourly inventory arrives. Rather than a static severity, each match is scored in context: exploit availability, EPSS, the asset's exposure, and business criticality decide where it lands in the queue. If an affected version is present anywhere across your portfolio, it surfaces automatically with a prioritised remediation path.

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Data from the NVD, CISA KEV catalog and FIRST EPSS. CVSS 3.1 base score shown where available.