# Optima Express IDX <= 8.7.8 - Cross-Site Request Forgery to Registration Key Takeover and Blog Credential Disclosure via 'reg' Parameter

- **ID:** WPSEC-2026-1863
- **Plugin:** Optima Express IDX (`optima-express`), https://wordpress.org/plugins/optima-express/
- **Affected versions:** all versions before 9.0.0
- **Fixed in:** 9.0.0 (Update to 9.0.0 or later.)
- **Severity:** Medium 5.4 (CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:N)
- **Weakness:** CWE-352
- **Usage among sites WPSec scans:** plugin Low, affected versions None seen (as of 2026-10-28)
- **Attack surface analysis:** https://attacksurface.wpsec.com/plugin/optima-express
- **Fix released:** 2026-10-27
- **Published:** 2026-10-28
- **URL:** https://wpsec.com/vuln/WPSEC-2026-1863/

## Description

The Optima Express IDX plugin for WordPress is vulnerable to Cross-Site Request Forgery via the 'reg' parameter of the Register admin page in all versions up to, and including, 8.7.8, due to missing nonce validation. Loading the page with a 'reg' value immediately stored that value as the site's registration key and ran activation with it. This makes it possible for unauthenticated attackers to rebind the site's IDX registration to a key they control, if they can trick a site administrator into clicking a crafted link. In versions that include the AI Blog Post feature, the activation request also creates an application password for the plugin's Author-level 'optima-express' user. That password and the site's REST base URL are sent to the iHomefinder service under the attacker's key, which can let the attacker publish content on the site with Author privileges.

## References

- https://wpsec.com/vuln/WPSEC-2026-1863/
- https://plugins.svn.wordpress.org/optima-express/tags/9.0.0/
- https://wordpress.org/plugins/optima-express/

Source: WPSec, https://wpsec.com/vuln/WPSEC-2026-1863/

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.