# CVE-2024-21495: Use of Insufficiently Random Values in github.com/greenpau/caddy-security

> Insecure randomness in Caddy security plugin allows attackers to predict nonces and secrets, enabling OAuth replay attacks and MFA bypass.

- **Severity:** Medium 6.5 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/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:** Not needed
- **Fix available:** No
- **Published:** 17 Feb 2024
- **Updated:** 5 Sep 2024
- **Also known as:** GHSA-c7vf-m394-m4x4, GO-2024-2565

## What is CVE-2024-21495?

CVE-2024-21495 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

Versions of the package github.com/greenpau/caddy-security before 1.0.42 are vulnerable to Insecure Randomness due to using an insecure random number generation library which could possibly be predicted via a brute-force search. Attackers could use the potentially predictable nonce value used for authentication purposes in the OAuth flow to conduct OAuth replay attacks. In addition, insecure randomness is used while generating multifactor authentication (MFA) secrets and creating API keys in the database package.

Weakness: CWE-330 (Use of Insufficiently Random Values)

## Which versions are affected by CVE-2024-21495?

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 1.0.42 | None |
| `github.com/greenpau/caddy-security` | Go | All versions to 1.0.42 | None |

Products: Greenpau Caddy-Security.

## How do I fix CVE-2024-21495?

No fix has been published for CVE-2024-21495 yet. Limit exposure of the affected software until one is available.

## Is CVE-2024-21495 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2024-21495 exists.

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

- [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-2024-21493](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-2024-21495 and fix it if it is affected.

What it is: CVE-2024-21495 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: It is not confirmed as exploited in the wild, but public exploit code for CVE-2024-21495 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 1.0.42; no fix listed
- github.com/greenpau/caddy-security (Go): affected all versions up to 1.0.42; 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-2024-21495/ (Markdown: https://insights.sbomify.com/CVE-2024-21495/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2024-21495
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2024-21495
- OSV: https://osv.dev/vulnerability/CVE-2024-21495

---
From sbomify Insights: https://insights.sbomify.com/CVE-2024-21495/
Summaries are generated and may contain mistakes; the official description above is the record.