{"id":"CVE-2026-4406","url":"https://www.cyber-defence.io/tools/cve/CVE-2026-4406","generatedAt":"2026-10-28T09:42:28.943Z","title":"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.","description":"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.","published":"2026-04-08T00:16:05.000Z","lastModified":"2026-07-24T23:10:01.000Z","status":"Deferred","sourceIdentifier":"security@wordfence.com","cvss":{"version":"3.1","score":4.7,"severity":"MEDIUM","vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:L/I:L/A:N"},"cwe":["CWE-79"],"affected":[],"epss":{"score":0.00356,"percentile":0.29151,"date":"2026-10-27","history":[]},"kev":{"listed":false},"exploits":{"count":0,"verified":false,"firstPublished":null,"source":"Exploit-DB (https://gitlab.com/exploit-database/exploitdb)","entries":[]},"verdict":{"level":"low","text":"Lower severity and a low EPSS score (0.36%). Track it; it rarely justifies an emergency change on its own."},"changes":[],"references":[{"url":"https://docs.gravityforms.com/gravityforms-change-log/","source":"security@wordfence.com"},{"url":"https://plugins.trac.wordpress.org/browser/gravityforms/trunk/common.php#L8267","source":"security@wordfence.com"},{"url":"https://plugins.trac.wordpress.org/browser/gravityforms/trunk/includes/config/class-gf-config-collection.php#L56","source":"security@wordfence.com"},{"url":"https://plugins.trac.wordpress.org/browser/gravityforms/trunk/includes/config/class-gf-config-service-provider.php#L144","source":"security@wordfence.com"},{"url":"https://plugins.trac.wordpress.org/browser/gravityforms/trunk/includes/config/items/class-gf-config-global.php#L22","source":"security@wordfence.com"},{"url":"https://www.wordfence.com/threat-intel/vulnerabilities/id/4126d452-65a9-48f5-a3f5-5be1b8fff80c?source=cve","source":"security@wordfence.com"}],"sources":{"nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-4406","epss":"https://www.first.org/epss/","kev":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog","exploitdb":"https://www.exploit-db.com/"},"licence":"CC BY 4.0 — link back to the CVE Explorer if you publish the results; upstream data remains subject to its own terms."}