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Vulnerability · Published Oct 30, 2026 · Assigned by Wordfence

CVE-2026-89435Formidable Forms <= 6.35 - Authenticated (Subscriber+) Arbitrary Plugin Installation via 'file_url' Parameter

High 8.8

In plain English

A high-severity injection in Formidable Forms – Contact Form, Survey, Quiz, Payment, Calculator Form & Custom Form Builder from strategy11team. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.4% (higher than 34% of all known vulnerabilities).

Severity (CVSS 3.1)8.8High
Exploit odds (30 days)0.4%top 66.4% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack toolingNoneno public tooling known

Official 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).

Affected products (as reported)

VendorProductVersions
strategy11team Formidable Forms – Contact Form, Survey, Quiz, Payment, Calculator Form & Custom Form Builder 0 – through 6.35

Weakness: CWE-74 · Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

References