Description

The Ninja Forms WordPress plugin before 3.14.10 does not prevent user-supplied query-string input, used to pre-populate a form field's default value, from being processed as a shortcode, allowing unauthenticated attackers to execute arbitrary shortcodes registered on the site when a form so configured is embedded on a public page.

Executive Summary

Technical Details

Mitigations

References

Additional Metadata

{
  "score": "4.8",
  "pubDate": "2026-08-06T22:16:48.040Z",
  "pubdate": "2026-08-06T22:16:48.040Z",
  "executiveSummary": "An arbitrary shortcode execution vulnerability exists in the Ninja Forms WordPress plugin prior to version 3.14.10, stemming from improper handling of user-supplied query-string input intended for form field default value pre-population. The vulnerability impacts WordPress sites utilizing the Ninja Forms plugin where affected forms are embedded on publicly accessible pages. Unauthenticated remote attackers can exploit this flaw to execute arbitrary registered WordPress shortcodes by manipulating the query string parameters of a targeted page. Successful exploitation can lead to unintended shortcode rendering, potential execution of sensitive underlying functionality exposed by registered third-party or core shortcodes, information disclosure, or further application compromise depending on the capabilities of the shortcodes available within the WordPress environment. The risk implication is significant as it bypasses authentication controls and allows unauthenticated interactions with internal WordPress parser mechanisms through crafted HTTP requests. Remediation requires updating the Ninja Forms plugin to version 3.14.10 or later, where input sanitization and processing logic for pre-populated field values are properly secured.",
  "technicalDetails": "The root cause of the vulnerability resides in the insecure processing of user-supplied query-string parameters within the Ninja Forms plugin prior to version 3.14.10. Specifically, when a form is configured to accept default field values via the URL query string, the input values are not adequately sanitized or stripped of shortcode delimiters before being passed to the WordPress shortcode parsing engine. Consequently, any string containing WordPress shortcode syntax (such as square brackets enclosing registered shortcode identifiers and arguments) supplied via the query string is evaluated and executed by the application context when the form is rendered on a public-facing page.\nThe vulnerable component is the input handling and pre-population mechanism responsible for mapping query string parameters to form field default values. Affected versions include all instances of the Ninja Forms WordPress plugin before 3.14.10. The exploitation requires zero authentication or privilege requirements, as the attack surface is exposed over the network via standard HTTP/HTTPS requests to public pages containing an embedded, appropriately configured Ninja Forms instance.\nThe step-by-step attack flow proceeds as follows: First, an unauthenticated attacker identifies a public-facing web page containing an embedded Ninja Forms form that utilizes query-string pre-population for one or more of its fields. Second, the attacker crafts a malicious HTTP GET request targeting this public URL, appending a specially crafted query string parameter designed to inject an arbitrary WordPress shortcode instead of expected scalar input data. Third, when the victim or attacker requests the page, the Ninja Forms plugin retrieves the user-supplied query-string input and assigns it as the default value for the targeted form field. Fourth, during the rendering phase of the form or its surrounding context, the WordPress application processes the input string through its parsing routines, evaluating the injected shortcode syntax. Fifth, the registered shortcode executes within the security context of the web application, yielding the output of the shortcode execution or triggering the intended side effects of the invoked functionality."
}