# CVE-2026-9721: Book a Room Event Calendar <= 1.9 - Cross-Site Request Forgery to Settings Update

> Attackers can trick administrators into modifying plugin database settings via CSRF, potentially compromising data integrity and security.

- **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:** 24 Jun 2026
- **Updated:** 24 Jun 2026
- **Also known as:** GHSA-pfhp-jm8f-gx6g

## What is CVE-2026-9721?

CVE-2026-9721 is a medium-severity vulnerability in chuhpl Book a Room Event Calendar, published on 24 Jun 2026. 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 Book a Room Event Calendar plugin for WordPress is vulnerable to Cross-Site Request Forgery in all versions up to, and including, 1.9. This is due to missing or incorrect nonce validation on the settings_form()/update_settings() functionality. The plugin's options page handler dispatches on the 'action' POST parameter and calls update_settings(), which persists plugin configuration (including the external database host, username, password, prefix, database name, encryption key, and registration page URL) via update_option(), without ever generating a nonce field in the settings form or verifying one (no wp_nonce_field(), check_admin_referer(), or wp_verify_nonce() exists anywhere in the plugin). This makes it possible for unauthenticated attackers to modify the plugin's database connection settings 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-2026-9721?


## How do I fix CVE-2026-9721?

No fix has been published for CVE-2026-9721 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-9721 being exploited?

There is no known exploitation of CVE-2026-9721 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-9721 and fix it if it is affected.

What it is: CVE-2026-9721 is a medium-severity vulnerability in chuhpl Book a Room Event Calendar, published on 24 Jun 2026. 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-2026-9721 in the wild and no public exploit code.

Affected product: chuhpl Book a Room Event Calendar. 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-2026-9721/ (Markdown: https://insights.sbomify.com/CVE-2026-9721/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-9721
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-9721
- OSV: https://osv.dev/vulnerability/CVE-2026-9721

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-9721/
Summaries are generated and may contain mistakes; the official description above is the record.