CVE-2026-89435: Formidable Forms content injection vulnerability
high 8.8 published 2026-10-30
- Affected versions
- 6.35 and older
- Fixed in
- 7.0 *
- Latest version
- 7.0
- Severity
- High · CVSS 8.8
- Active installs
- 300,000+
- Type
- Content injection
* The source does not name a fixed version; this is the first wordpress.org release after the last affected version.
What an attacker needs
- Access: A logged-in account with Subscriber-level access or higher.
CVSS vector (score by Wordfence): CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
What to do now
- Update Formidable Forms to 7.0 or newer: Dashboard → Updates, or Plugins → “update now”.
- If you cannot update right away, deactivate it until you can.
- Turn on auto-updates for it: Plugins → “Enable auto-updates” on its row.
- Not sure which version you run? Check your version against every known Formidable Forms issue.
With WP-CLI:
wp plugin get formidable --field=version. - If you ran an affected version and something looks off (new admin users, spam pages, redirects), run the free scan below.
The advisory
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).
References
- NVD CVE-2026-89435 nvd.nist.gov
- Wordfence advisory www.wordfence.com
- Code change (fix) plugins.trac.wordpress.org
- Plugin source plugins.trac.wordpress.org
Related
Ran an affected version? Check your site for signs of a hack
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Where this data comes from
- CVE record, score and references: NIST National Vulnerability Database (NVD), checked 2026-11-04. This product uses data from the NVD API but is not endorsed or certified by the NVD.
- Versions and install counts: wordpress.org/plugins/formidable (Plugins API), fetched 2026-11-01.
- The summary, “what an attacker needs” and “what to do” sections are our plain-English reading of the record and the plugin's release history; the quoted description is the record's own text. Spot an error? Email Daniel.