Chatterbug Forms <= 1.0.2 — Unauthenticated Arbitrary File Upload via File Upload via Public Form Submission

Am I affected?

• Check your version: in wp-admin go to Plugins → Installed Plugins and read the version under Chatterbug Forms – Fast, Flexible WordPress Form Builder.
• No admin access? Run a passive check of your site. It reads public files only.
• No account is needed to exploit this. Treat any exposed site on an affected version as at risk.

What to do

1. Update to version 1.1, or a newer patched version
2. Rotate administrator passwords and application secrets if the site ran a vulnerable version while publicly reachable.
3. Watch Chatterbug Forms – Fast, Flexible WordPress Form Builder to get an email when the next vulnerability is published.

Advisory

Source description from Wordfence Intelligence, credited to samathakeeling.

The Chatterbug Forms – Fast, Flexible WordPress Form Builder plugin for WordPress is vulnerable to Arbitrary File Upload in all versions up to, and including, 1.0.2 via the cbforms_check_form_submissions function. This is due to missing server-side file extension validation in cbforms_check_form_submissions(), where the allowed-type check defaults to the uploaded file's own extension when no field restriction is configured, trivially allowing any extension including .php. This makes it possible for unauthenticated attackers to upload files that may be executable, which makes remote code execution possible. The submission nonce printed inline on every public page containing a Chatterbug form is freely obtainable by unauthenticated visitors and therefore does not constitute an effective access control barrier.

Exploits & references

Proof-of-concept & detection

No public proof-of-concept or detection template is known for this vulnerability.

Advisories & patches

• Advisorywordfence.com

Related CVEs

Timeline

1. Nov 12, 2026

   CVE published

   Severity critical, CVSS 9.8

2. Nov 13, 2026

   Record last updated