CVE-2026-30851: GO-2026-4639 - Caddy forward_auth copy_headers allows Identity Injection and Privilege Escalation in github.com/caddyserver/caddy

CVE-2026-30851 · Severity: low · CVSS 3.1 · Published 2026-03-10

Caddy forward_auth copy_headers allows Identity Injection and Privilege Escalation in github.com/caddyserver/caddy

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

Quick answers

Is CVE-2026-30851 exploited in the wild?
No. Junglewise Threat Intelligence has no report of CVE-2026-30851 being exploited in the wild.
How severe is CVE-2026-30851?
Low severity, with a CVSS score of 3.1, published 10 March 2026.
Which products and versions are affected?
github.com/caddyserver/caddy/v2 (Go) SEMVER:introduced=2.10.0,fixed=2.11.2; github.com/caddyserver/caddy/v2/modules/caddyhttp/reverseproxy (Go) SEMVER:introduced=2.10.0,fixed=2.11.2.
Is there a fix for CVE-2026-30851?
Yes. github.com/caddyserver/caddy/v2 (Go): upgrade to 2.11.2 or later; github.com/caddyserver/caddy/v2/modules/caddyhttp/reverseproxy (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-2026-30851?
Check whether you run github.com/caddyserver/caddy/v2 (Go) or github.com/caddyserver/caddy/v2/modules/caddyhttp/reverseproxy (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/reverseproxy (Go): upgrade to 2.11.2 or later
    go get github.com/caddyserver/caddy/v2/modules/caddyhttp/reverseproxy@v2.11.2

Affected products

  • github.com/caddyserver/caddy/v2 (Go) SEMVER:introduced=2.10.0,fixed=2.11.2
  • github.com/caddyserver/caddy/v2/modules/caddyhttp/reverseproxy (Go) SEMVER:introduced=2.10.0,fixed=2.11.2

Identifiers

  • CVE-2026-30851
  • GHSA-7r4p-vjf4-gxv4
  • GO-2026-4639

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