# CVE-2021-4387: Opal Estate <= 1.6.11 - Cross-Site Request Forgery Bypass

> Unauthenticated attackers can trick administrators into modifying featured property settings via forged requests in the Opal Estate WordPress plugin.

- **Severity:** Medium 4.3 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** A user has to click or open something
- **Fix available:** No
- **Published:** 1 Jul 2023
- **Updated:** 8 Apr 2026
- **Also known as:** GHSA-x597-6f24-323f

## What is CVE-2021-4387?

CVE-2021-4387 is a medium-severity vulnerability in wpopal Opal Estate, published on 1 Jul 2023. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.

### Official description

The Opal Estate plugin for WordPress is vulnerable to Cross-Site Request Forgery in versions up to, and including, 1.6.11. This is due to missing or incorrect nonce validation on the opalestate_set_feature_property() and opalestate_remove_feature_property() functions. This makes it possible for unauthenticated attackers to set and remove featured properties via a forged request granted they can trick a site administrator into performing an action such as clicking on a link.

Weakness: CWE-352 (Cross-Site Request Forgery)

## Which versions are affected by CVE-2021-4387?

It affects 1 product.


Products: Wpopal Opal Estate.

## How do I fix CVE-2021-4387?

No fix has been published for CVE-2021-4387 yet. Limit exposure of the affected software until one is available.

## Is CVE-2021-4387 being exploited?

There is no known exploitation of CVE-2021-4387 in the wild and no public exploit code.

## Other vulnerabilities in wpopal Opal Estate

- [CVE-2021-4388](https://insights.sbomify.com/CVE-2021-4388/): Opal Estate <= 1.6.11 - Missing Authorization (medium 4.3)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2021-4387 and fix it if it is affected.

What it is: CVE-2021-4387 is a medium-severity vulnerability in wpopal Opal Estate, published on 1 Jul 2023. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.
Exploitation: There is no known exploitation of CVE-2021-4387 in the wild and no public exploit code.

Affected product: wpopal Opal Estate. 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-2021-4387/ (Markdown: https://insights.sbomify.com/CVE-2021-4387/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2021-4387
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-4387
- OSV: https://osv.dev/vulnerability/CVE-2021-4387

---
From sbomify Insights: https://insights.sbomify.com/CVE-2021-4387/
Summaries are generated and may contain mistakes; the official description above is the record.