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

Source: https://junglewise.ai/threats/cve-2026-30851-caddy-forward-auth-copy-headers-does-not-strip-client-supplied  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-03-10  
License: CC BY 4.0 with a link back

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)](https://junglewise.ai/threats/technologies/github-com-caddyserver-caddy-v2). Vendors: [Go](https://junglewise.ai/threats/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

  ```sh
  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

  ```sh
  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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- [GO-2026-5730 - Caddy Fix Bypass in github.com/caddyserver/caddy](https://junglewise.ai/threats/go-2026-5730-caddy-fix-bypass-in-github-com-caddyserver-caddy-baf17ba5)
- [Caddyserver Caddy XSS bypass in stripHTML template function](https://junglewise.ai/threats/cve-2026-52846-caddyserver-caddy-xss-bypass-in-striphtml-template-function)