Formidable Forms <= 6.35 - Authenticated (Subscriber+) Arbitrary Plugin Installation via 'file_url' Parameter
Summary
| CVE | CVE-2026-89435 |
|---|---|
| State | PUBLISHED |
| Assigner | Wordfence |
| Source Priority | CVE Program / NVD first with legacy fallback |
| Published | 2026-10-30 07:16:34 UTC |
| Updated | 2026-10-30 07:16:34 UTC |
| 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). |
Risk And Classification
Primary CVSS: v3.1 8.8 HIGH from [email protected]
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Problem Types: CWE-74 | CWE-74 CWE-74 Improper Neutralization of Special Elements in Output Used by a Downstream Component
| Version | Source | Type | Score | Severity | Vector |
|---|---|---|---|---|---|
| 3.1 | [email protected] | Primary | 8.8 | HIGH | CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H |
| 3.1 | CNA | DECLARED | 8.8 | HIGH | CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H |
CVSS v3.1 Breakdown
Attack Vector
NetworkAttack Complexity
LowPrivileges Required
LowUser Interaction
NoneScope
UnchangedConfidentiality
HighIntegrity
HighAvailability
HighCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Vendor Declared Affected Products
| Source | Vendor | Product | Version | Platforms |
|---|---|---|---|---|
| CNA | Strategy11team | Formidable Forms Contact Form Survey Quiz Payment Calculator Form Custom Form Builder | affected 6.35 semver | Not specified |
References
| Reference | Source | Link | Tags |
|---|---|---|---|
| plugins.trac.wordpress.org/changeset | [email protected] | plugins.trac.wordpress.org | |
| plugins.trac.wordpress.org/browser/formidable/tags/6.35/classes/helpers/FrmAppHelper.php | [email protected] | plugins.trac.wordpress.org | |
| plugins.trac.wordpress.org/browser/formidable/tags/6.35/classes/controllers/FrmAppContro... | [email protected] | plugins.trac.wordpress.org | |
| plugins.trac.wordpress.org/browser/formidable/tags/6.35/classes/controllers/FrmAddonsCon... | [email protected] | plugins.trac.wordpress.org | |
| plugins.trac.wordpress.org/changeset/3746820/formidable/trunk/classes/controllers/FrmAdd... | [email protected] | plugins.trac.wordpress.org | |
| plugins.trac.wordpress.org/browser/formidable/tags/6.35/classes/controllers/FrmAddonsCon... | [email protected] | plugins.trac.wordpress.org | |
| plugins.trac.wordpress.org/browser/formidable/tags/6.35/classes/controllers/FrmAddonsCon... | [email protected] | plugins.trac.wordpress.org | |
| www.wordfence.com/threat-intel/vulnerabilities/id/87661de6-e835-495e-9bd2-4d64b... | [email protected] | www.wordfence.com | |
| CVE Program record | CVE.ORG | www.cve.org | canonical |
| NVD vulnerability detail | NVD | nvd.nist.gov | canonical, analysis |
Vendor Comments And Credit
Discovery Credit
CNA: Supakiad S. (m3ez) (en)
Additional Advisory Data
| Source | Time | Event |
|---|---|---|
| CNA | 2026-09-11T19:53:34.000Z | Vendor Notified |
| CNA | 2026-10-29T18:46:13.000Z | Disclosed |
There are currently no legacy QID mappings associated with this CVE.