Sander Horsman

Sander Horsman is a security researcher credited with 5 disclosed vulnerabilities in the WordSec WordPress vulnerability database, ranked #795 of 3,823 contributors. The disclosure was published in 2026.

Their research concentrates on Authorization Bypass Through User-Controlled Key, which accounts for 2 of their findings (40%). Other recurring categories include Code Injection, Missing Authorization. The average CVSS score across these disclosures is 7.6, peaking at 8.2. Severity breakdown: 0 critical and 4 high.

The most affected software includes Fluent Forms (2), Email Subscribers & Newsletters (1), MW WP Form (1), across 4 distinct plugins, themes and core versions in total.

All 5 disclosed issues have since received a vendor fix. The most severe finding, "Fluent Forms <= 6.2.0 - Authenticated (Subscriber+) Authorization Bypass via 'table' Parameter", scores 8.2 out of 10.