CVE-2026-1261 in MetForm Pro Plugin
Summary
by MITRE • 03/10/2026
The MetForm Pro plugin for WordPress is vulnerable to Stored Cross-Site Scripting via the Quiz feature in all versions up to, and including, 3.9.6 due to insufficient input sanitization and output escaping. This makes it possible for unauthenticated attackers to inject arbitrary web scripts in pages that will execute whenever a user accesses an injected page.
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Analysis
by VulDB Data Team • 03/13/2026
The MetForm Pro plugin for WordPress represents a significant security vulnerability through its Quiz feature implementation, affecting all versions up to and including 3.9.6. This stored cross-site scripting vulnerability stems from inadequate input sanitization and output escaping mechanisms within the plugin's codebase, creating a persistent threat vector that can be exploited by unauthenticated attackers. The flaw exists in how the plugin processes and handles user input within the quiz functionality, allowing malicious actors to inject malicious scripts that persist in the application's database and execute whenever users access affected pages.
The technical nature of this vulnerability aligns with CWE-79, which specifically addresses cross-site scripting flaws where insufficient input validation and output escaping create opportunities for attackers to inject malicious code. The stored aspect of this vulnerability means that the injected scripts are permanently saved within the application's database rather than being reflected in HTTP request parameters, making the attack more persistent and potentially more damaging. Attackers can craft malicious payloads that exploit the plugin's quiz feature to inject JavaScript code that executes in the context of other users' browsers when they view pages containing the injected content.
The operational impact of this vulnerability extends beyond simple script execution, as it can enable attackers to perform various malicious activities including session hijacking, data theft, and redirection to malicious websites. Users who access pages containing the stored malicious scripts become victims of the attack, with their browser sessions potentially compromised and sensitive information at risk of exposure. The unauthenticated nature of the attack means that no prior access credentials are required, making this vulnerability particularly dangerous as it can be exploited by anyone with access to the affected WordPress site. This threat is exacerbated by the widespread use of WordPress and its plugins, as attackers can potentially compromise numerous sites simultaneously.
Mitigation strategies for this vulnerability should prioritize immediate patching of the MetForm Pro plugin to version 3.9.7 or later, which should contain the necessary fixes for input sanitization and output escaping. System administrators should implement comprehensive monitoring of their WordPress installations to detect any suspicious activity or unauthorized modifications to plugin files. Input validation should be strengthened through the implementation of strict sanitization routines that filter and validate all user inputs before processing, while output escaping mechanisms should be enhanced to ensure that any potentially malicious content is properly encoded before being rendered in web pages. Additionally, organizations should consider implementing web application firewalls and content security policies to provide additional layers of protection against similar vulnerabilities in the future. The ATT&CK framework categorizes this type of vulnerability under T1566, which involves the exploitation of vulnerabilities to gain initial access, with the stored XSS representing a common method for establishing persistent access to target systems.