CVE-2026-30852: GO-2026-4644 - Caddy's vars_regexp double-expands user input, leaking env vars and files in github.com/caddyserver/caddy

CVE-2026-30852 · Severity: medium · CVSS 4 · Published 2026-03-10

Caddy's vars_regexp double-expands user input, leaking env vars and files in github.com/caddyserver/caddy

Technologies: github.com/caddyserver/caddy/v2 (Go). Vendors: Go.

Quick answers

Is CVE-2026-30852 exploited in the wild?
No. Junglewise Threat Intelligence has no report of CVE-2026-30852 being exploited in the wild.
How severe is CVE-2026-30852?
Medium severity, with a CVSS score of 4, published 10 March 2026.
Which products and versions are affected?
github.com/caddyserver/caddy/v2 (Go) SEMVER:introduced=2.7.5,fixed=2.11.2; github.com/caddyserver/caddy/v2/modules/caddyhttp (Go) SEMVER:introduced=2.7.5,fixed=2.11.2.
Is there a fix for CVE-2026-30852?
Yes. github.com/caddyserver/caddy/v2 (Go): upgrade to 2.11.2 or later; github.com/caddyserver/caddy/v2/modules/caddyhttp (Go): upgrade to 2.11.2 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
Am I affected by CVE-2026-30852?
Check whether you run github.com/caddyserver/caddy/v2 (Go) or github.com/caddyserver/caddy/v2/modules/caddyhttp (Go) at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

How to fix

  • github.com/caddyserver/caddy/v2 (Go): upgrade to 2.11.2 or later
    go get github.com/caddyserver/caddy/v2@v2.11.2
  • github.com/caddyserver/caddy/v2/modules/caddyhttp (Go): upgrade to 2.11.2 or later
    go get github.com/caddyserver/caddy/v2/modules/caddyhttp@v2.11.2

Affected products

  • github.com/caddyserver/caddy/v2 (Go) SEMVER:introduced=2.7.5,fixed=2.11.2
  • github.com/caddyserver/caddy/v2/modules/caddyhttp (Go) SEMVER:introduced=2.7.5,fixed=2.11.2

Identifiers

  • CVE-2026-30852
  • GHSA-m2w3-8f23-hxxf
  • GO-2026-4644

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