# WebinarPress <= 1.33.30 - Unauthenticated Reflected Cross-Site Scripting via 'content' Parameter

- **ID:** WPSEC-2026-0547
- **Plugin:** WebinarPress – Webinar System for WordPress (`wp-webinarsystem`), https://wordpress.org/plugins/wp-webinarsystem/
- **Affected versions:** from 1.33.21 before 1.33.31
- **Fixed in:** 1.33.31 (Update to 1.33.31 or later.)
- **Severity:** Medium 6.1 (CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N)
- **Weakness:** CWE-79
- **Usage among sites WPSec scans:** plugin Low, affected versions Low (as of 2026-10-07)
- **Attack surface analysis:** https://attacksurface.wpsec.com/plugin/wp-webinarsystem
- **Fix released:** 2026-10-06
- **Published:** 2026-10-07
- **URL:** https://wpsec.com/vuln/WPSEC-2026-0547/

## Description

The WebinarPress plugin for WordPress is vulnerable to Reflected Cross-Site Scripting via the 'content' parameter of its embedded iframe handler in versions 1.33.21 up to, and including, 1.33.30 due to a missing capability check and insufficient input sanitization and output escaping. This makes it possible for unauthenticated attackers to inject arbitrary web scripts in pages that execute if they can successfully trick a user into performing an action such as submitting a crafted form.

## References

- https://wpsec.com/vuln/WPSEC-2026-0547/
- https://plugins.svn.wordpress.org/wp-webinarsystem/tags/1.33.31/
- https://wordpress.org/plugins/wp-webinarsystem/

Source: WPSec, https://wpsec.com/vuln/WPSEC-2026-0547/

License: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Free to use, share and adapt, also commercially, if you credit WPSec and link to this advisory.