# CVE-2024-21493: Improper Validation of Array Index in github.com/greenpau/caddy-security

> A missing nil check in the Caddy security plugin causes a panic during configuration parsing, leading to a denial of service.

- **Severity:** Medium 5.3 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L/E:P`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 17 Feb 2024
- **Updated:** 1 Aug 2024
- **Also known as:** GHSA-8h95-jcp5-pjpr, GO-2024-2564

## What is CVE-2024-21493?

CVE-2024-21493 is a medium-severity vulnerability in github.com/greenpau/caddy-security, published on 17 Feb 2024. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

All versions of the package github.com/greenpau/caddy-security are vulnerable to Improper Validation of Array Index when parsing a Caddyfile. Multiple parsing functions in the affected library do not validate whether their input values are nil before attempting to access elements, which can lead to a panic (index out of range). Panics during the parsing of a configuration file may introduce ambiguity and vulnerabilities, hindering the correct interpretation and configuration of the web server.

Weakness: CWE-129 (Improper Validation of Array Index)

## Which versions are affected by CVE-2024-21493?

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-2024-21493?

No fix has been published for CVE-2024-21493 yet. Limit exposure of the affected software until one is available.

## Is CVE-2024-21493 being exploited?

There is no known exploitation of CVE-2024-21493 in the wild and no public exploit code.

## 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-2024-21494](https://insights.sbomify.com/CVE-2024-21494/): Authentication Bypass by Spoofing in github.com/greenpau/caddy-security (medium 5.4)
- [CVE-2024-21497](https://insights.sbomify.com/CVE-2024-21497/): Open Redirect in github.com/greenpau/caddy-security (medium 5.4)
- [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-2024-21493 and fix it if it is affected.

What it is: CVE-2024-21493 is a medium-severity vulnerability in github.com/greenpau/caddy-security, published on 17 Feb 2024. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2024-21493 in the wild and no public exploit code.

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-2024-21493/ (Markdown: https://insights.sbomify.com/CVE-2024-21493/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2024-21493
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2024-21493
- OSV: https://osv.dev/vulnerability/CVE-2024-21493

---
From sbomify Insights: https://insights.sbomify.com/CVE-2024-21493/
Summaries are generated and may contain mistakes; the official description above is the record.