CVE-2026-65439 in Ultimate Addons for Contact Form 7 Plugin
Summary
by MITRE • 07/28/2026
Unauthenticated Cross Site Scripting (XSS) in Ultimate Addons for Contact Form 7 <=3.5.45 versions.
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Analysis
by VulDB Data Team • 07/28/2026
The vulnerability under examination represents an unauthenticated cross site scripting flaw within the Ultimate Addons for Contact Form 7 plugin, affecting versions up to and including 3.5.45. This issue stems from inadequate input validation and output escaping mechanisms within the plugin's codebase, specifically when processing data submitted through contact forms. The vulnerability allows attackers to inject malicious javascript code that executes in the context of other users' browsers without requiring authentication credentials.
The technical root cause of this vulnerability aligns with CWE-79, which defines improper neutralization of input during web page generation as a primary weakness leading to XSS attacks. The flaw manifests when user-supplied data containing script tags or malicious payloads is processed and rendered back to the browser without appropriate sanitization or encoding. This occurs particularly in areas where the plugin handles form submissions, shortcode parameters, or administrative configurations that are subsequently displayed on web pages. Attackers can exploit this by crafting contact form submissions containing malicious javascript code, which then gets executed when other users view the affected pages or interact with the compromised forms.
The operational impact of this vulnerability extends beyond simple data theft or session hijacking. An attacker could potentially leverage this XSS flaw to perform actions on behalf of authenticated users, manipulate form data, redirect users to malicious sites, or even establish persistent backdoors within the target environment. The unauthenticated nature of the attack means that any visitor to the compromised website could be affected, making this a particularly dangerous vulnerability for public-facing websites. Additionally, the widespread adoption of Contact Form 7 and its add-ons increases the potential attack surface significantly.
Mitigation strategies should focus on immediate patching of the vulnerable plugin versions to the latest secure releases where the XSS vulnerabilities have been addressed. Organizations should implement comprehensive input validation mechanisms that sanitize all user-supplied data before processing or displaying it on web pages. The implementation of Content Security Policy headers can provide an additional layer of protection against XSS attacks by restricting script execution. Regular security audits and vulnerability assessments of third-party plugins should be conducted to identify potential security gaps. According to ATT&CK framework, this vulnerability maps to T1059.007 for the use of scripting and T1566 for social engineering techniques that could exploit such vulnerabilities. Organizations should also consider implementing Web Application Firewalls and monitoring for suspicious script injection patterns in their web traffic logs to detect potential exploitation attempts.