CVE-2025-66500: Foxit PDF Editor Cloud

Medium severity, CVSS 5.4. EPSS: 0.2% chance of exploitation in the next 30 days.

A stored cross-site scripting (XSS) vulnerability exists in webplugins.foxit.com. A postMessage handler fails to validate the message origin and directly assigns externalPath to a script source, allowing an attacker to execute arbitrary JavaScript when a crafted postMessage is received.

Affected products

• Foxit PDF Editor Cloud: before 2025-12-01 (fixed in 2025-12-01)

Published 2025-12-19. Last modified 2026-06-17.