CVE-2026-84999 Pie Register Premium <= 3.8.4.0 - Unauthenticated Arbitrary File Upload via piereg_file_upload AJAX Handler
- Exploited in the wild
- Not known
- Fix
- None listed
What is CVE-2026-84999?
CVE-2026-84999 is a critical vulnerability in Pie Register Premium, published on 28 Oct 2026.
Official description
The Pie Register Premium plugin for WordPress is vulnerable to Unrestricted File Type Upload in all versions up to, and including, 3.8.4.0 via the piereg_file_upload function. This is due to the plugin performing file type validation via wp_check_filetype and wp_check_filetype_and_ext but never checking whether those validation calls produced errors before move_uploaded_file() is called, combined with no nonce or capability check on the AJAX handler. This makes it possible for unauthenticated attackers to upload files of dangerous types (e.g. PHP scripts) that may be executable, which makes remote code execution possible. The server returns the generated destination filename in the response, giving the attacker the exact path needed to trigger the uploaded file.
Weakness: CWE-434
Which versions are affected by CVE-2026-84999?
How do I fix CVE-2026-84999?
No fix has been published for CVE-2026-84999 yet. Limit exposure of the affected software until one is available.
Is CVE-2026-84999 being exploited?
There is no known exploitation of CVE-2026-84999 in the wild and no public exploit code.
Sources
Also known as GHSA-356m-cxhj-j59p.