CVE-2026-109384: The Innovative Form Builder arbitrary file upload vulnerability

high 8.8 published 2026-10-28 · updated 2026-10-29

Affected versions: 1.5.1 and older
Fixed in: 1.5.2 *
Latest version: 1.5.2
Severity: High · CVSS 8.8
Active installs: 1,000+
Type: Arbitrary file upload

* 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: None. No account or login is needed.

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 The Innovative Form Builder to 1.5.2 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 The Innovative Form Builder issue. With WP-CLI: wp plugin get ivyforms --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 The Innovative Form Builder – IvyForms plugin for WordPress is vulnerable to Arbitrary File Upload in all versions up to, and including, 1.5.1 via the filterFiletypeAndExt function. This is due to insufficient file type validation due to the absence of a dangerous-extension denylist in the allowed-extensions sanitizer and deliberate override of WordPress's native MIME and extension defences via a registered wp_check_filetype_and_ext filter. This makes it possible for authenticated attackers, with custom-level access and above, to upload files that may be executable, which makes remote code execution possible. An authenticated attacker with the custom add_edit_forms capability must first configure a File Upload field with a dangerous extension (e.g., php) in the allowed-extensions list; once that form is published, any unauthenticated visitor can trigger the actual file upload via the publicly accessible /wp-json/ivyforms/v1/form/submission/ REST route.

Description from the CVE record, published by Wordfence (the CVE Numbering Authority), via the NVD entry for CVE-2026-109384.

References

NVD CVE-2026-109384 nvd.nist.gov
Wordfence advisory www.wordfence.com
Code change (fix) plugins.trac.wordpress.org
Plugin source plugins.trac.wordpress.org

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/ivyforms (Plugins API), fetched 2026-11-04.
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.