CVE-2025-26940: Pie Register Premium Path Traversal Flaw

CVE-2025-26940 Overview

CVE-2025-26940 is a path traversal vulnerability affecting the Pie Register Premium WordPress plugin. The flaw impacts all versions up to and including 3.8.3.2. An authenticated attacker with low privileges can traverse directories outside the intended path to delete non-arbitrary files on the server.

The vulnerability is tracked under CWE-35: Path Traversal: '.../...//'. Successful exploitation degrades application availability by removing files the plugin should not be able to reach. The issue was published to the National Vulnerability Database on March 15, 2025.

Critical Impact
Authenticated attackers can delete files outside the plugin's intended scope, causing disruption to WordPress site availability and functionality.

Affected Products

Pie Register Premium plugin for WordPress
All versions from initial release through 3.8.3.2
WordPress installations using the affected plugin for registration workflows

Discovery Timeline

2025-03-15 - CVE-2025-26940 published to NVD
2026-06-17 - Last updated in NVD database

Technical Details for CVE-2025-26940

Vulnerability Analysis

The vulnerability resides in file-handling logic within Pie Register Premium that fails to sanitize user-supplied path input. An attacker with authenticated access can supply crafted path sequences to reach files outside the plugin's expected directory scope.

Exploitation requires network access and a valid low-privilege account on the target WordPress site. No user interaction is required to trigger the flaw. The scope is marked as changed because the vulnerability affects resources beyond the plugin's own security boundary.

The impact is limited to availability, specifically non-arbitrary file deletion. The attacker cannot select any file freely but can remove files reachable through the flawed path resolution. Confidentiality and integrity are not directly affected.

Root Cause

The root cause is improper neutralization of path traversal sequences such as ../ in a file path parameter processed by the plugin. The plugin accepts a filename or path from an authenticated request and passes it to a file deletion routine without validating that the resolved path stays within an allowed directory. This maps to CWE-35, which covers relative path traversal using variations like .../...//.

Attack Vector

An authenticated user submits a request to a vulnerable plugin endpoint with a path parameter containing traversal characters. The plugin resolves the path relative to its working directory, escapes the intended boundary, and invokes a deletion function on the resolved target. The result is removal of a file the requester should not be able to touch.

No verified public exploit or proof-of-concept has been published. See the Patchstack Vulnerability Report for the technical writeup.

Detection Methods for CVE-2025-26940

Indicators of Compromise

Unexpected deletion of files under the WordPress installation directory, especially plugin, theme, or upload paths
HTTP requests to Pie Register plugin endpoints containing ../ or URL-encoded traversal sequences such as %2e%2e%2f
Authenticated POST requests from low-privilege subscriber or contributor accounts targeting file-management actions in the plugin
WordPress error log entries referencing missing files that were present prior to the request

Detection Strategies

Inspect web server access logs for requests to Pie Register endpoints carrying path traversal patterns in query strings or POST bodies
Correlate authenticated session activity with file deletion events in filesystem audit logs
Deploy a web application firewall rule that blocks traversal sequences in parameters bound for plugin actions
Monitor plugin behavior for file operations that resolve outside the plugin's own directory

Monitoring Recommendations

Enable filesystem integrity monitoring on wp-content/, wp-includes/, and the WordPress root to catch unauthorized deletions
Forward WordPress and web server logs to a centralized log platform and alert on traversal patterns in plugin request paths
Track user account activity for low-privilege accounts issuing administrative-style requests to the Pie Register plugin

How to Mitigate CVE-2025-26940

Immediate Actions Required

Identify all WordPress sites running Pie Register Premium version 3.8.3.2 or earlier and prioritize them for update
Apply the vendor-supplied patched release as soon as it is available from the plugin distributor
Restrict new user registration and audit existing low-privilege accounts for suspicious activity
Take a full backup of the WordPress site, database, and wp-content/ directory before making changes

Patch Information

Refer to the Patchstack Vulnerability Report for the fixed version reference. Administrators should update to a Pie Register Premium release later than 3.8.3.2 once published by the vendor. Confirm the installed version through the WordPress plugins dashboard after applying the update.

Workarounds

Deactivate the Pie Register Premium plugin until a patched version is installed if registration functionality is not business-critical
Deploy a WAF rule that blocks traversal characters and encoded variants in requests to plugin endpoints
Restrict access to /wp-admin/admin-ajax.php and Pie Register endpoints using IP allowlisting where feasible
Enforce strong authentication and limit account creation to trusted users to reduce the pool of potential attackers

bash

# Example ModSecurity rule to block path traversal in plugin requests
SecRule REQUEST_URI "@contains pie-register" \
  "chain,phase:2,deny,status:403,id:1002694,\
  msg:'CVE-2025-26940 Pie Register path traversal attempt'"
  SecRule ARGS|REQUEST_BODY "@rx (\.\./|\.\.\\|%2e%2e%2f|%2e%2e/)" \
    "t:none,t:urlDecodeUni,t:lowercase"