CVE-2026-15256

Unauthenticated Cross Site Scripting (XSS) in Ninja Forms versions up to 3.15.3. An attacker can inject malicious script without authentication.

The Ninja Forms plugin version 3.14.8 and prior for WordPress Multisite contains an incorrect authorization vulnerability that allows a subsite Administrator to trigger network-wide deletion of all Ninja Forms data. Attackers can send a crafted POST request to the admin-ajax.php endpoint with the nf_delete_all_data action and a per-site nonce to invoke migration routines that unconditionally iterate all blogs via switch_to_blog(), dropping all nf3_* tables and clearing options and transients across every subsite in the network without requiring super-admin or network-admin privileges.

The Ninja Forms plugin for WordPress versions 3.10.4 through 3.14.9 contains an unauthenticated stored cross-site scripting vulnerability in the Repeatable Fieldset feature. The parseSubmissionIndex() function accepts arbitrary strings as submission indexes without numeric validation, and admin_form_element() interpolates the index directly into HTML without escaping. An unauthenticated attacker can submit a public form with a crafted repeater child key containing malicious script payloads, which execute in an administrator's browser when viewing submissions in the WordPress admin panel.

The Ninja Forms plugin for WordPress before version 3.0.23 (when the Uploads add-on is activated) contains path traversal and unrestricted file upload vulnerabilities. This allows an attacker to traverse the file system to access files and execute code via the name and tmp_name parameters in includes/fields/upload.php.

The Ninja Forms plugin for WordPress (versions up to and including 3.15.4) is vulnerable to Stored Cross-Site Scripting via Paragraph Text (RTE) field submission due to insufficient input sanitization and output escaping. An unauthenticated attacker can inject arbitrary web scripts into pages that execute when a user accesses the injected page. This is only exploitable when the targeted Paragraph Text field has the Rich Text Editor (RTE) option enabled.

The Ninja Forms plugin in versions up to and including 3.15.3 contains an unauthenticated Cross Site Scripting (XSS) vulnerability. An attacker can inject malicious script into the page.

Ninja Forms 3.15.3 stores an anonymous non-RTE textarea value and renders it without safe HTML encoding in the legacy submission editor. An attacker can break out of the textarea with stored script. When an Administrator opens the attacker-known direct submission URL, the script runs in the WordPress admin origin.

The Ninja Forms WordPress plugin 3.15.3 does not escape submitted form field values before outputting them on the submission edit screen in the admin area. An unauthenticated user can submit values through a public form that then execute in the browser of any high-privileged user who reviews the submission.

The Ninja Forms WordPress plugin 3.15.3 does not prevent user-submitted form field values from being deserialised when an administrator later exports form submissions to CSV. This allows unauthenticated attackers to perform PHP Object Injection; if a suitable POP chain is present via another installed plugin or theme, this can lead to actions such as arbitrary file operations or remote code execution.

The Ninja Forms plugin for WordPress is vulnerable to PHP Object Injection in all versions up to 3.14.6 via deserialization of untrusted input. Authenticated attackers with administrator access can inject a PHP object. No known POP chain exists, but if another plugin or theme provides one, it may allow file deletion, data theft, or code execution.