# CVE-2021-24217: Facebook for WordPress < 3.0.0 - PHP Object Injection with POP Chain

> An attacker can achieve remote code execution by supplying malicious PHP objects to the Facebook for WordPress plugin via unsafe deserialization.

- **Severity:** High 8.1 (`CVSS:3.1/AV:N/AC:H/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:** 12 Apr 2021
- **Updated:** 3 Aug 2024
- **Also known as:** GHSA-w6px-4fhm-xxgc

## What is CVE-2021-24217?

CVE-2021-24217 is a high-severity unsafe deserialization vulnerability in Unknown Facebook for WordPress, published on 12 Apr 2021. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

The run_action function of the Facebook for WordPress plugin before 3.0.0 deserializes user supplied data making it possible for PHP objects to be supplied creating an Object Injection vulnerability. There was also a useable magic method in the plugin that could be used to achieve remote code execution.

Weakness: CWE-502 (Deserialization of Untrusted Data)

## Which versions are affected by CVE-2021-24217?

It affects 1 product.


Products: Facebook Facebook.

## How do I fix CVE-2021-24217?

No fix has been published for CVE-2021-24217 yet. Limit exposure of the affected software until one is available.

## Is CVE-2021-24217 being exploited?

There is no known exploitation of CVE-2021-24217 in the wild and no public exploit code.

## Other vulnerabilities in Unknown Facebook for WordPress

- [CVE-2021-24218](https://insights.sbomify.com/CVE-2021-24218/): Facebook for WordPress 3.0.0-3.0.3 - CSRF to Stored XSS and Settings Deletion (high 8.8)
- [CVE-2014-6392](https://insights.sbomify.com/CVE-2014-6392/): Cross-site scripting in n/a (medium 4.3)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2021-24217 and fix it if it is affected.

What it is: CVE-2021-24217 is a high-severity unsafe deserialization vulnerability in Unknown Facebook for WordPress, published on 12 Apr 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-2021-24217 in the wild and no public exploit code.

Affected product: Unknown Facebook for WordPress. 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-2021-24217/ (Markdown: https://insights.sbomify.com/CVE-2021-24217/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2021-24217
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-24217
- OSV: https://osv.dev/vulnerability/CVE-2021-24217

---
From sbomify Insights: https://insights.sbomify.com/CVE-2021-24217/
Summaries are generated and may contain mistakes; the official description above is the record.