---
id: CVE-2026-84999
title: >-
  Pie Register Premium <= 3.8.4.0 - Unauthenticated Arbitrary File Upload via
  piereg_file_upload AJAX Handler
summary: >-
  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…
severity: critical
cvss: 9.8
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H'
cvssSource: cna
cwe:
  - CWE-434
vendor: Pie Register
product: Pie Register Premium
affected:
  - premium <= 3.8.4.0
ssvc:
  exploitation: none
  automatable: 'yes'
  technicalImpact: total
  timestamp: '2026-10-29T01:35:34.731950Z'
published: '2026-10-28'
updated: '2026-10-29'
sourceUpdated: '2026-10-29T01:51:59.919Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-84999'
references:
  - url: >-
      https://www.wordfence.com/threat-intel/vulnerabilities/id/8385dd30-28e5-4572-8504-2f3e7029bad6?source=cve
  - url: 'https://pieregister.com/'
tags:
  - cve.org
epss: 0.00483
epssPercentile: 0.41768
ingestedAt: '2026-10-28T03:02:57.614Z'
---

## Overview

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.

## Affected

- `premium <= 3.8.4.0`

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.