CVE-2026-118235: SimpleForm arbitrary file upload vulnerability
critical 9.8 published 2026-10-31 · updated 2026-11-02
- Affected versions
- 3.10.2 and older
- Fixed in
- 3.11.0 *
- Latest version
- 3.11.0
- Severity
- Critical · CVSS 9.8
- Active installs
- 30+
- 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:N/UI:N/S:U/C:H/I:H/A:H
What to do now
- Update SimpleForm to 3.11.0 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 SimpleForm issue.
With WP-CLI:
wp plugin get simple-form --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 SimpleForm – Form Maker to Chat Apps with Quiz, Poll and Multi Lead Notifications plugin for WordPress is vulnerable to Arbitrary File Upload in all versions up to, and including, 3.10.2 via the handle_upload function. This is due to missing server-side file key allowlist and pre-sanitization extension derivation that allows a trailing-dot filename to bypass all extension and MIME validation in handle_upload. This makes it possible for unauthenticated attackers to upload files that may be executable, which makes remote code execution possible. The only access control is a nonce that is printed into every public form's data-nonce attribute, making it trivially obtainable by any unauthenticated visitor on a page embedding the form shortcode.
References
- NVD CVE-2026-118235 nvd.nist.gov
- Wordfence advisory www.wordfence.com
- Code change (fix) plugins.trac.wordpress.org
- plugins.svn.wordpress.org plugins.svn.wordpress.org
- Plugin source plugins.trac.wordpress.org
Related
Ran an affected version? Check your site for signs of a hack
The free scan reads the public side of your site and looks for spam pages, hidden redirects, injected scripts and blacklist entries. No login, no install, about a minute.
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/simple-form (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.