# CVE-2024-21496: Cross-site Scripting in github.com/greenpau/caddy-security

> An attacker can execute malicious scripts in a user's browser via the Referer header, potentially compromising user sessions.

- **Severity:** Medium 6.1 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/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:** 6 Nov 2024
- **Also known as:** GHSA-ff72-ff42-c3gw, GO-2024-2559

## What is CVE-2024-21496?

CVE-2024-21496 is a medium-severity cross-site scripting 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 Cross-site Scripting (XSS) via the Referer header, due to improper input sanitization. Although the Referer header is sanitized by escaping some characters that can allow XSS (e.g., [&], [<], [>], ["], [']), it does not account for the attack based on the JavaScript URL scheme (e.g., javascript:alert(document.domain)// payload). Exploiting this vulnerability may not be trivial, but it could lead to the execution of malicious scripts in the context of the target user’s browser, compromising user sessions.

Weakness: CWE-79 (Improper Neutralization of Input During Web Page Generation)

## Which versions are affected by CVE-2024-21496?

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: Authcrunch Caddy-Security.

## How do I fix CVE-2024-21496?

No fix has been published for CVE-2024-21496 yet. Limit exposure of the affected software until one is available.

## Is CVE-2024-21496 being exploited?

There is no known exploitation of CVE-2024-21496 in the wild and no public exploit code.

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

- [CVE-2023-52430](https://insights.sbomify.com/CVE-2023-52430/): caddy-security plugin for Caddy vulnerable to reflected Cross-site Scripting (medium 5.4)
- [CVE-2024-21498](https://insights.sbomify.com/CVE-2024-21498/): Server-Side Request Forgery in github.com/greenpau/caddy-security (medium 5.3)
- [CVE-2024-21492](https://insights.sbomify.com/CVE-2024-21492/): Insufficient Session Expiration in github.com/greenpau/caddy-security (medium 4.8)
- [CVE-2024-21500](https://insights.sbomify.com/CVE-2024-21500/): Improper Restriction of Excessive Authentication Attempts in github.com/greenpau/caddy-security (medium 4.8)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2024-21496 and fix it if it is affected.

What it is: CVE-2024-21496 is a medium-severity cross-site scripting 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: There is no known exploitation of CVE-2024-21496 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-2024-21496/ (Markdown: https://insights.sbomify.com/CVE-2024-21496/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2024-21496
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2024-21496
- OSV: https://osv.dev/vulnerability/CVE-2024-21496

---
From sbomify Insights: https://insights.sbomify.com/CVE-2024-21496/
Summaries are generated and may contain mistakes; the official description above is the record.