CVE-2026-89435 Details
Description
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 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).
A vulnerability allowing arbitrary plugin installation has been identified in the Formidable Forms WordPress plugin, specifically in versions through 6.35. This issue arises from inadequate validation of URL prefixes in the 'file_url' parameter, enabling authenticated attackers with subscriber-level access or higher to install arbitrary plugins on the server. The vulnerability exploitation requires the site to be using the free version of Formidable Forms, as the pro version alters the plugin's behavior.
Users are advised to update the Formidable Forms plugin to version 7.0 or later.
Metrics
CVSS 4.0 Severity and Vector Strings:
VolerionCVSS 3.x Severity and Vector Strings:
No data available for CVSS Version 2.0 on this CVE.
Volerion
Assessed Oct 30, 2026CISA-ADP
Assessed Oct 30, 2026References to Advisories, Solutions, and Tools
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Weakness Enumeration
| CWE-ID | CWE Name | Source |
|---|---|---|
| CWE-74 | Improper Neutralization of Special Elements in Output Used by a Downstream Component ('Injection') | [email protected] |
Affected Products
| Product | Versions |
|---|---|
| Formidable Forms | <= 6.35 |
CPE
Remediation
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Change History
2 change records found show changes
| Date | Action | Recorded By |
|---|---|---|
| Oct 30, 2026 | CVE Modified | CISA-ADP |
| Oct 30, 2026 | New CVE Received | [email protected] |