Executive brief
Happyforms is a popular WordPress plugin used to create and manage contact forms. A critical security flaw allows unauthorized individuals to inject malicious code into the website without needing a login. This could lead to a complete takeover of the site, theft of sensitive customer data, or a total service outage.
Technical details
A PHP Object Injection vulnerability exists in the Happyforms plugin for WordPress due to improper handling of untrusted data during deserialization (CWE-502). An unauthenticated remote attacker can exploit this by sending specially crafted input to the application. If a suitable Property-Oriented Programming (POP) chain is present on the server, the attacker can achieve remote code execution, perform SQL injection, or access sensitive files via path traversal. The vulnerability is resolved in version 1.26.14.
Affected products
- Happyforms Happyforms <= 1.26.13
Timeline
- 2026-05-20: other: Reported by researcher longnv719
- 2026-06-04: advisory: Patchstack published advisory and mitigation rules
- 2026-06-15: disclosed: CVE published to NVD