WP Express Checkout (Fast Payments via PayPal & Stripe) Security & Risk Analysis

The wp-express-checkout v2.4.6 plugin exhibits a generally good security posture with several strong practices, including the exclusive use of prepared statements for SQL queries and a high rate of output escaping (82%). The absence of critical or high-severity known vulnerabilities and the fact that all past CVEs are patched are positive indicators. However, the plugin has a notable attack surface with 30 AJAX handlers, 5 of which lack authentication checks. While the taint analysis did not reveal any critical or high-severity unsanitized flows, the presence of 3 flows with unsanitized paths, even if assessed as low or medium severity by the analysis tool, warrants attention. The history of 2 medium-severity CVEs, with the most recent in March 2024, indicates that while vulnerabilities are being addressed, there's a pattern of issues that could be exploited if left unpatched. The combination of unprotected AJAX endpoints and a history of vulnerabilities suggests a moderate risk level. Further investigation into the nature of the 3 unsanitized flows and the historical CVEs is recommended.