# CVE-2021-21329: Multi Factor Authentication Token Improperly Validated On User Login

> Attackers can bypass multi-factor authentication to log into RATCF accounts if MFA is enabled, compromising user accounts.

- **Severity:** High 8.7 (`CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 8 Mar 2021
- **Updated:** 3 Aug 2024
- **Also known as:** GHSA-fw57-f7mq-9q85

## What is CVE-2021-21329?

CVE-2021-21329 is a high-severity authentication bypass vulnerability in ractf core, published on 8 Mar 2021. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

RATCF is an open-source framework for hosting Cyber-Security Capture the Flag events. In affected versions of RATCF users with multi factor authentication enabled are able to log in without a valid token. This is fixed in commit cebb67b.

Weakness: CWE-287 (Improper Authentication)

## Which versions are affected by CVE-2021-21329?

It affects 1 product.


Products: Ratcf Ratcf.

## How do I fix CVE-2021-21329?

No fix has been published for CVE-2021-21329 yet. Limit exposure of the affected software until one is available.

## Is CVE-2021-21329 being exploited?

There is no known exploitation of CVE-2021-21329 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2021-21329 and fix it if it is affected.

What it is: CVE-2021-21329 is a high-severity authentication bypass vulnerability in ractf core, published on 8 Mar 2021. 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-2021-21329 in the wild and no public exploit code.

Affected product: ractf core. No package-level version data is available, so check the vendor advisory linked from the reference page.

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-2021-21329/ (Markdown: https://insights.sbomify.com/CVE-2021-21329/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2021-21329
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-21329
- OSV: https://osv.dev/vulnerability/CVE-2021-21329

---
From sbomify Insights: https://insights.sbomify.com/CVE-2021-21329/
Summaries are generated and may contain mistakes; the official description above is the record.