CVE-2021-4367
Published: April 11, 2026
Official Description
The Flo Forms – Easy Drag & Drop Form Builder plugin for WordPress is vulnerable to Stored Cross-Site Scripting via Options Change by using the flo_import_forms_options AJAX action in versions up to, and including, 1.0.35 due to insufficient input sanitization and output escaping along with missing capability checks. This makes it possible for authenticated attackers, like subscribers, to inject arbitrary web scripts in pages that will execute whenever a user accesses an injected page.
Technical Analysis
CVE-2021-4367 requires local access, meaning attackers must already have a foothold on the target system.
Exploitation requires some privileges, which limits the exposure to scenarios where an attacker has already gained initial access.
CISA has added CVE-2021-4367 to the Known Exploited Vulnerabilities (KEV) catalog, confirming active exploitation in the wild. U.S. federal agencies are required to patch this within the mandated timeframe, and all organizations should treat remediation as urgent.
Affected Vendors & Products
Exploit & PoC Resources
Quick Facts
Recommended Actions
- →Apply vendor patches immediately
- →Monitor CVE-2021-4367 in threat intel feeds
- →Review IDS/IPS signatures for exploitation attempts
- !CISA KEV: Federal agencies must patch per BOD 22-01 timeline
- !Active exploitation confirmed — treat as P1