# CVE-2021-4073: RegistrationMagic <= 5.0.1.7 Authentication Bypass

> Unauthenticated attackers can log in as any user, including administrators, by exploiting missing identity validation in the social login function.

- **Severity:** Critical 9.8 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 14 Dec 2021
- **Updated:** 14 Feb 2025
- **Also known as:** GHSA-3858-cvv4-qvj7

## What is CVE-2021-4073?

CVE-2021-4073 is a critical authentication bypass vulnerability in RegistrationMagic, published on 14 Dec 2021. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

The RegistrationMagic WordPress plugin made it possible for unauthenticated users to log in as any site user, including administrators, if they knew a valid username on the site due to missing identity validation in the social login function social_login_using_email() of the plugin. This affects versions equal to, and less than, 5.0.1.7.

Weakness: CWE-287 (Improper Authentication)

## Which versions are affected by CVE-2021-4073?

It affects 1 product.


Products: Metagauss Registrationmagic.

## How do I fix CVE-2021-4073?

No fix has been published for CVE-2021-4073 yet. Limit exposure of the affected software until one is available.

## Is CVE-2021-4073 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2021-4073 exists.

Public exploit code:

- RegistrationMagic <= 5.0.1.7 - Authentication Bypass (nuclei): http/cves/2021/CVE-2021-4073.yaml

## Other vulnerabilities in RegistrationMagic

- [CVE-2017-20208](https://insights.sbomify.com/CVE-2017-20208/): RegistrationMagic - Custom Registration Forms <= 3.7.9.2 - PHP Object Injection (critical 9.8)
- [CVE-2024-10508](https://insights.sbomify.com/CVE-2024-10508/): Auth bypass in RegistrationMagic – Custom Registration Forms, User Registration, Payment, and User Login (critical 9.8)
- [CVE-2023-2499](https://insights.sbomify.com/CVE-2023-2499/): RegistrationMagic <= 5.2.1.0 - Authentication Bypass (critical 9.8)
- [CVE-2024-1990](https://insights.sbomify.com/CVE-2024-1990/): SQL injection in RegistrationMagic – Custom Registration Forms, User Registration, Payment, and User Login (high 8.8)
- [CVE-2024-1991](https://insights.sbomify.com/CVE-2024-1991/): Privilege escalation in RegistrationMagic – Custom Registration Forms, User Registration, Payment, and User Login (high 8.8)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2021-4073 and fix it if it is affected.

What it is: CVE-2021-4073 is a critical authentication bypass vulnerability in RegistrationMagic, published on 14 Dec 2021. 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-2021-4073 exists.

Affected product: RegistrationMagic. 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-2021-4073/ (Markdown: https://insights.sbomify.com/CVE-2021-4073/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2021-4073
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-4073
- OSV: https://osv.dev/vulnerability/CVE-2021-4073

---
From sbomify Insights: https://insights.sbomify.com/CVE-2021-4073/
Summaries are generated and may contain mistakes; the official description above is the record.