CVE-2026-4406
MediumCVSS 4.7Exploitation Probability (EPSS)
Low risk28th percentile - higher than 28% of all known CVEs
Summary
The Gravity Forms plugin for WordPress up to version 2.9.30 is vulnerable to Reflected XSS via the `form_ids` parameter in the `gform_get_config` AJAX action. This is due to the `GFCommon::send_json()` method outputting JSON data wrapped in HTML comments with a `Content-Type: text/html` header instead of `application/json`. The `wp_json_encode()` function does not HTML-encode angle brackets, allowing injected HTML/script tags. The `config_nonce` is publicly embedded on every page with a Gravity Forms form, making it identical for all unauthenticated visitors within a 12-hour nonce tick. This allows unauthenticated attackers to inject arbitrary web scripts if they can trick a user into clicking a link. The vulnerability does not work against authenticated users.
Risk Assessment
The risk is that an unauthenticated attacker can remotely inject malicious scripts, potentially leading to session theft, redirects, or other actions on the site, but only against unauthenticated users.
Recommendation
Update the Gravity Forms plugin to a version above 2.9.30 and consider adding a Content-Type: application/json header for AJAX responses.
Original NVD description (English source)
The Gravity Forms plugin for WordPress is vulnerable to Reflected Cross-Site Scripting via the `form_ids` parameter in the `gform_get_config` AJAX action in all versions up to, and including, 2.9.30. This is due to the `GFCommon::send_json()` method outputting JSON-encoded data wrapped in HTML comment delimiters using `echo` and `wp_die()`, which serves the response with a `Content-Type: text/html` header instead of `application/json`. The `wp_json_encode()` function does not HTML-encode angle brackets within JSON string values, allowing injected HTML/script tags in `form_ids` array values to be parsed and executed by the browser. The required `config_nonce` is generated with `wp_create_nonce('gform_config_ajax')` and is publicly embedded on every page that renders a Gravity Forms form, making it identical for all unauthenticated visitors within the same 12-hour nonce tick. This makes it possible for unauthenticated attackers to inject arbitrary web scripts in pages that execute if they can successfully trick a user into performing an action such as clicking on a link. This vulnerability cannot be exploited against users who are authenticated on the target system, but could be used to alter the target page.