WordPress security changelog
HIGH CVE-2026-4350 Deferred

Perfmatters: Filesystem traversal

Perfmatters is affected by filesystem traversal. Exploitation requires at least subscriber-level access. A crafted path can escape the intended directory and reach files or directories elsewhere on the server. The published affected range is <= 2.5.9.1.

CVE / CNA score 8.1 CVSS 3.1 · security@wordfence.com
NVD score Pending NVD has not published its own CVSS assessment.
Component
Perfmatters
Plugin slug
perfmatters
Affected
<= 2.5.9.1
Safe version
> 2.5.9.1
Published
Apr 03, 2026
Weakness
CWE-22 — Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')

This CVE was published Apr 03, 2026 and is one of 9 known issues for this plugin.

Update, patch or deactivate.

Update Perfmatters to a release after 2.5.9.1, or disable and remove it until a fixed version is available.

A safe version is available, so updating to that version or later is the preferred remediation. If an immediate update is not practical, consider a targeted application patch or temporarily restricting the affected functionality.

Deactivate only when warranted by your risk profile, or when advised by your hosting provider in the limited circumstances where the vulnerability cannot otherwise be mitigated. If you’re unsure which action is appropriate, contact Fused or your hosting provider for guidance.

Technical description

The Perfmatters plugin for WordPress is vulnerable to arbitrary file deletion via path traversal in all versions up to, and including, 2.5.9.1. This is due to the `PMCS::action_handler()` method processing the `$_GET['delete']` parameter without any sanitization, authorization check, or nonce verification. The unsanitized filename is concatenated with the storage directory path and passed to `unlink()`. This makes it possible for authenticated attackers, with Subscriber-level access and above, to delete arbitrary files on the server by using `../` path traversal sequences, including `wp-config.php` which would force WordPress into the installation wizard and allow full site takeover.

CVE / CNA vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:H

Primary and upstream sources