# CVE-2021-42362: WordPress Popular Posts <= 5.3.2 Authenticated Arbitrary File Upload

> Authenticated attackers with contributor access can upload malicious files to achieve remote code execution in the WordPress Popular Posts plugin.

- **Severity:** High 8.8 (`CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 17 Nov 2021
- **Updated:** 16 Sep 2024
- **Also known as:** GHSA-p9wv-phc4-8hqf

## What is CVE-2021-42362?

CVE-2021-42362 is a high-severity vulnerability in WordPress Popular Posts, published on 17 Nov 2021. Any signed-in user can exploit it over the network, with no action from the victim.

### Official description

The WordPress Popular Posts WordPress plugin is vulnerable to arbitrary file uploads due to insufficient input file type validation found in the ~/src/Image.php file which makes it possible for attackers with contributor level access and above to upload malicious files that can be used to obtain remote code execution, in versions up to and including 5.3.2.

Weakness: CWE-434 (Unrestricted Upload of File with Dangerous Type)

## Which versions are affected by CVE-2021-42362?

It affects 1 product.


Products: Wordpress Popular Posts Project Wordpress Popular Posts.

## How do I fix CVE-2021-42362?

No fix has been published for CVE-2021-42362 yet. Limit exposure of the affected software until one is available.

## Is CVE-2021-42362 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2021-42362 exists.

Public exploit code:

- Wordpress Popular Posts Authenticated RCE (metasploit)
- Wordpress Most Popular Post plugin vuln (github_poc): https://github.com/simonecris/CVE-2021-42362-PoC
- WordPress Plugin Popular Posts 5.3.2 - Remote Code Execution (RCE) (Authenticated) (exploitdb)
- The WordPress Popular Posts WordPress plugin is vulnerable to arbitrary file uploads due to insufficient input file type validation found in the ~/src/Image.php file which makes it possible for attackers with contributor level access and above to upload malicious files that can be used to obtain remote code execution, (github_poc): https://github.com/samiba6/CVE-2021-42362

## Other vulnerabilities in WordPress Popular Posts

- [CVE-2022-43468](https://insights.sbomify.com/CVE-2022-43468/): Business logic in WordPress Popular Posts (high 7.5)
- [CVE-2023-45607](https://insights.sbomify.com/CVE-2023-45607/): WordPress WordPress Popular Posts Plugin <= 6.3.2 is vulnerable to Cross Site Scripting (XSS) (medium 6.5)
- [CVE-2021-36872](https://insights.sbomify.com/CVE-2021-36872/): WordPress Popular Posts plugin <= 5.3.3 - Authenticated Persistent Cross-Site Scripting (XSS) vulnerability (medium 5.5)
- [CVE-2021-20746](https://insights.sbomify.com/CVE-2021-20746/): Cross-site scripting in WordPress Popular Posts (medium 5.4)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2021-42362 and fix it if it is affected.

What it is: CVE-2021-42362 is a high-severity vulnerability in WordPress Popular Posts, published on 17 Nov 2021. Any signed-in user can exploit it over the network, with no action from the victim.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2021-42362 exists.

Affected product: WordPress Popular Posts. 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-2021-42362/ (Markdown: https://insights.sbomify.com/CVE-2021-42362/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2021-42362
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-42362
- OSV: https://osv.dev/vulnerability/CVE-2021-42362

---
From sbomify Insights: https://insights.sbomify.com/CVE-2021-42362/
Summaries are generated and may contain mistakes; the official description above is the record.