{"id":"CVE-2026-89435","title":"Formidable Forms <= 6.35 - Authenticated (Subscriber+) Arbitrary Plugin Installation via 'file_url' Parameter","summary":"The Formidable Forms – WordPress Form Builder for Contact Forms, Calculators, Quizzes & More plugin for WordPress is vulnerable to Arbitrary Plugin Installation in all versions up to, and including, 6.35 via the 'file_url' parameter para…","severity":"high","cvss":8.8,"cvssVector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","cvssSource":"cna","cwe":["CWE-74"],"vendor":"strategy11team","product":"Formidable Forms – Contact Form, Survey, Quiz, Payment, Calculator Form & Custom Form Builder","affected":["formidable_forms_contact_form_survey_quiz_payment_calculator_form_custom_form_builder <= 6.35"],"ssvc":{"exploitation":"none","automatable":"no","technicalImpact":"total","timestamp":"2026-10-30T17:32:42.670504Z"},"published":"2026-10-30","updated":"2026-10-30","sourceUpdated":"2026-10-30T18:09:00.504Z","source":"CVEORG","sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-89435","references":[{"url":"https://www.wordfence.com/threat-intel/vulnerabilities/id/87661de6-e835-495e-9bd2-4d64b4718108?source=cve"},{"url":"https://plugins.trac.wordpress.org/browser/formidable/tags/6.35/classes/controllers/FrmAddonsController.php#L1514"},{"url":"https://plugins.trac.wordpress.org/browser/formidable/tags/6.35/classes/controllers/FrmAddonsController.php#L1489"},{"url":"https://plugins.trac.wordpress.org/browser/formidable/tags/6.35/classes/helpers/FrmAppHelper.php#L4934"},{"url":"https://plugins.trac.wordpress.org/browser/formidable/tags/6.35/classes/controllers/FrmAddonsController.php#L1459"},{"url":"https://plugins.trac.wordpress.org/browser/formidable/tags/6.35/classes/controllers/FrmAppController.php#L1167"},{"url":"https://plugins.trac.wordpress.org/changeset?reponame=&new=3750372%40formidable%2Ftags%2F7.0&old=3688662%40formidable%2Ftags%2F6.35"},{"url":"https://plugins.trac.wordpress.org/changeset/3746820/formidable/trunk/classes/controllers/FrmAddonsController.php"}],"tags":["cve.org"],"epss":0.00392,"epssPercentile":0.33623,"ingestedAt":"2026-11-05T16:24:31.316Z","slug":"CVE-2026-89435","body":"## Overview\n\nThe Formidable Forms – WordPress Form Builder for Contact Forms, Calculators, Quizzes & More plugin for WordPress is vulnerable to Arbitrary Plugin Installation in all versions up to, and including, 6.35 via the 'file_url' parameter parameter. This is due to insufficient URL prefix validation in validate_url_is_in_s3_bucket() and a permission callback that relies solely on a shared token obtainable by any user with the delegable frm_view_forms capability, without checking install_plugins or activate_plugins capabilities. This makes it possible for authenticated attackers, with subscriber-level access and above, to install arbitrary plugins on the server. Exploitation additionally requires that the site is free-only (Formidable Pro is NOT installed).\n\n## Affected\n\n- `formidable_forms_contact_form_survey_quiz_payment_calculator_form_custom_form_builder <= 6.35`\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.","depth":"twilight","depthScore":48,"depthScoreParts":{"impact":48.4,"likelihood":0.1,"exploitation":0,"ransomware":0},"changes":[]}