Gravity Forms Plugin up to 2.9.30 on WordPress Content-Type GFCommon::send_json form_ids cross site scripting

Summaryinfo

A vulnerability, which was classified as problematic, has been found in Gravity Forms Plugin up to 2.9.30 on WordPress. This affects the function GFCommon::send_json of the component Content-Type Handler. The manipulation of the argument form_ids leads to cross site scripting. This vulnerability is traded as CVE-2026-4406. It is possible to initiate the attack remotely. There is no exploit available.

Detailsinfo

A vulnerability, which was classified as problematic, has been found in Gravity Forms Plugin up to 2.9.30 on WordPress. This issue affects the function GFCommon::send_json of the component Content-Type Handler. The manipulation of the argument form_ids with an unknown input leads to a cross site scripting vulnerability. Using CWE to declare the problem leads to CWE-79. The product does not neutralize or incorrectly neutralizes user-controllable input before it is placed in output that is used as a web page that is served to other users. Impacted is integrity. The summary by CVE is:

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.

The weakness was shared by Anthony Cihan. It is possible to read the advisory at wordfence.com. The identification of this vulnerability is CVE-2026-4406 since 03/18/2026. The exploitation is known to be difficult. The attack may be initiated remotely. No form of authentication is needed for a successful exploitation. It demands that the victim is doing some kind of user interaction. Technical details of the vulnerability are known, but there is no available exploit. The attack technique deployed by this issue is T1059.007 according to MITRE ATT&CK.

There is no information about possible countermeasures known. It may be suggested to replace the affected object with an alternative product.

The vulnerability is also documented in the vulnerability database at CNNVD (CNNVD-202604-1897). Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.

Productinfo

Type

• WordPress Plugin

Name

• Gravity Forms Plugin

Version

• 2.9.0
• 2.9.1
• 2.9.2
• 2.9.3
• 2.9.4
• 2.9.5
• 2.9.6
• 2.9.7
• 2.9.8
• 2.9.9
• 2.9.10
• 2.9.11
• 2.9.12
• 2.9.13
• 2.9.14
• 2.9.15
• 2.9.16
• 2.9.17
• 2.9.18
• 2.9.19
• 2.9.20
• 2.9.21
• 2.9.22
• 2.9.23
• 2.9.24
• 2.9.25
• 2.9.26
• 2.9.27
• 2.9.28
• 2.9.29
• 2.9.30

CPE 2.3info

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CPE 2.2info

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Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.

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