CVE-2026-39449 Overview
CVE-2026-39449 is an unauthenticated Cross-Site Scripting (XSS) vulnerability affecting the Contact Form to Any API WordPress plugin in versions 3.0.3 and earlier. The flaw is categorized under [CWE-79], improper neutralization of input during web page generation. Attackers can inject arbitrary JavaScript that executes in the browser of any user who interacts with a crafted link or page. The vulnerability requires user interaction but no authentication, and it produces a scope change that affects resources beyond the vulnerable component.
Critical Impact
Unauthenticated attackers can execute arbitrary JavaScript in victim browsers, enabling session hijacking, credential theft, and administrative account takeover on affected WordPress sites.
Affected Products
- Contact Form to Any API WordPress plugin versions <= 3.0.3
- WordPress sites with the plugin installed and active
- Any web application instance exposing the plugin's input handling to unauthenticated users
Discovery Timeline
- 2026-06-15 - CVE-2026-39449 published to NVD
- 2026-06-17 - Last updated in NVD database
Technical Details for CVE-2026-39449
Vulnerability Analysis
The Contact Form to Any API plugin fails to properly sanitize and encode user-supplied input before rendering it in HTML output. This classic reflected or stored XSS condition allows attackers to inject script payloads into form fields or request parameters processed by the plugin. When the unsanitized content is later returned in a response page, the browser interprets the payload as executable JavaScript.
The attack reaches across security boundaries, allowing injected scripts to access resources outside the vulnerable component scope. Successful exploitation can compromise authenticated administrator sessions if an admin views the malicious content. The Patchstack advisory confirms the flaw is exploitable without authentication, increasing the attack surface to any visitor or anonymous user.
Root Cause
The root cause is missing or insufficient output encoding in the plugin's request handling and rendering pipeline. The plugin passes user-controlled data into HTML contexts without applying WordPress sanitization functions such as esc_html(), esc_attr(), or wp_kses(). This omission allows raw <script> tags and event-handler attributes to survive into the rendered DOM.
Attack Vector
An attacker crafts a request containing JavaScript payload data targeting the plugin's vulnerable parameter. The attacker then lures a victim into visiting the crafted URL or page through phishing, social engineering, or a malicious link. Because the attack vector is network-based and requires only user interaction, exploitation does not depend on attacker privileges on the target site.
The vulnerability mechanism is described in the Patchstack advisory for Contact Form to Any API. No verified public proof-of-concept code is currently available.
Detection Methods for CVE-2026-39449
Indicators of Compromise
- Web server access logs containing requests with encoded <script>, onerror=, onload=, or javascript: payloads targeting Contact Form to Any API endpoints
- Unexpected outbound HTTP requests from administrator browsers to attacker-controlled domains
- WordPress user sessions or cookies appearing in external services or attacker logs
- Newly created administrator accounts or modified user roles following form submissions
Detection Strategies
- Inspect WordPress plugin inventory for contact-form-to-any-api with a version at or below 3.0.3
- Deploy Web Application Firewall (WAF) rules to flag XSS payload patterns in request parameters handled by the plugin
- Review browser Content Security Policy (CSP) violation reports for inline script execution attempts
- Correlate referrer headers showing external links pointing to plugin endpoints with encoded payloads
Monitoring Recommendations
- Enable verbose WordPress audit logging for plugin form submissions and administrative actions
- Alert on administrator authentication followed by configuration changes from unusual IP addresses
- Monitor for DOM-based anomalies and unexpected <script> injection patterns in cached HTML
- Track plugin update status across all managed WordPress instances
How to Mitigate CVE-2026-39449
Immediate Actions Required
- Identify all WordPress installations running Contact Form to Any API version 3.0.3 or earlier
- Update the plugin to a fixed version as soon as the vendor publishes one; consult the Patchstack advisory for patch status
- Disable or remove the plugin if a patched version is not yet available
- Force password resets and session invalidation for all administrator accounts if exploitation is suspected
Patch Information
The vulnerability affects Contact Form to Any API versions <= 3.0.3. Administrators should consult the Patchstack vulnerability database entry for the latest fixed release information and apply the update through the WordPress plugin dashboard.
Workarounds
- Deactivate the Contact Form to Any API plugin until a patched version is installed
- Deploy a WAF with rules blocking common XSS payload patterns targeting the plugin's request parameters
- Enforce a strict Content Security Policy (CSP) that disallows inline scripts and unauthorized script sources
- Restrict administrator access to trusted IP ranges to reduce the risk of session compromise via XSS
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
