# CVE-2024-21494: Authentication Bypass by Spoofing in github.com/greenpau/caddy-security

> Attackers can bypass authentication by spoofing IP addresses via the X-Forwarded-For header in the Caddy security plugin.

- **Severity:** Medium 5.4 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:N/E:P`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** A user has to click or open something
- **Fix available:** No
- **Published:** 17 Feb 2024
- **Updated:** 24 Apr 2025
- **Also known as:** GHSA-vj36-3ccr-6563, GO-2024-2558

## What is CVE-2024-21494?

CVE-2024-21494 is a medium-severity authentication bypass vulnerability in github.com/greenpau/caddy-security, published on 17 Feb 2024. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.

### Official description

All versions of the package github.com/greenpau/caddy-security are vulnerable to Authentication Bypass by Spoofing via the X-Forwarded-For header due to improper input sanitization. An attacker can spoof an IP address used in the user identity module (/whoami API endpoint). This could lead to unauthorized access if the system trusts this spoofed IP address.

Weakness: CWE-79 (Improper Neutralization of Input During Web Page Generation), CWE-290 (Authentication Bypass by Spoofing)

## Which versions are affected by CVE-2024-21494?

3 open source packages ship an affected version, including github.com/greenpau/caddy-security. It affects 1 product.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `github.com/greenpau/caddy-security` | Go | All versions | None |
| `github.com/greenpau/caddy-security` | Go | All versions to 1.1.23 | None |
| `github.com/greenpau/caddy-security` | Go | All versions to 1.1.23 | None |

Products: Greenpau Caddy-Security.

## How do I fix CVE-2024-21494?

No fix has been published for CVE-2024-21494 yet. Limit exposure of the affected software until one is available.

## Is CVE-2024-21494 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2024-21494 exists.

## Other vulnerabilities in github.com/greenpau/caddy-security

- [CVE-2024-21495](https://insights.sbomify.com/CVE-2024-21495/): Use of Insufficiently Random Values in github.com/greenpau/caddy-security (medium 6.5)
- [CVE-2024-21497](https://insights.sbomify.com/CVE-2024-21497/): Open Redirect in github.com/greenpau/caddy-security (medium 5.4)
- [CVE-2024-21493](https://insights.sbomify.com/CVE-2024-21493/): Improper Validation of Array Index in github.com/greenpau/caddy-security (medium 5.3)
- [CVE-2024-21499](https://insights.sbomify.com/CVE-2024-21499/): Improper Neutralization of HTTP Headers in github.com/greenpau/caddy-security (medium 4.3)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2024-21494 and fix it if it is affected.

What it is: CVE-2024-21494 is a medium-severity authentication bypass vulnerability in github.com/greenpau/caddy-security, published on 17 Feb 2024. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2024-21494 exists.

Affected packages and fixed versions:
- github.com/greenpau/caddy-security (Go): affected all versions; no fix listed
- github.com/greenpau/caddy-security (Go): affected all versions up to 1.1.23; no fix listed
- github.com/greenpau/caddy-security (Go): affected all versions up to 1.1.23; no fix listed

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2024-21494/ (Markdown: https://insights.sbomify.com/CVE-2024-21494/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2024-21494
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2024-21494
- OSV: https://osv.dev/vulnerability/CVE-2024-21494

---
From sbomify Insights: https://insights.sbomify.com/CVE-2024-21494/
Summaries are generated and may contain mistakes; the official description above is the record.