Perfmatters Plugin up to 2.5.9 on WordPress PMCS::action_handler snippets path traversal

Summaryinfo

A vulnerability marked as critical has been reported in Perfmatters Plugin up to 2.5.9 on WordPress. This vulnerability affects the function PMCS::action_handler. This manipulation of the argument snippets causes path traversal. The identification of this vulnerability is CVE-2026-4351. It is possible to initiate the attack remotely. There is no exploit available. It is suggested to upgrade the affected component.

Detailsinfo

A vulnerability classified as critical was found in Perfmatters Plugin up to 2.5.9 on WordPress. Affected by this vulnerability is the function PMCS::action_handler. The manipulation of the argument snippets with an unknown input leads to a path traversal vulnerability. The CWE definition for the vulnerability is CWE-22. The product uses external input to construct a pathname that is intended to identify a file or directory that is located underneath a restricted parent directory, but the product does not properly neutralize special elements within the pathname that can cause the pathname to resolve to a location that is outside of the restricted directory. As an impact it is known to affect integrity, and availability. The summary by CVE is:

The Perfmatters plugin for WordPress is vulnerable to arbitrary file overwrite via path traversal in all versions up to, and including, 2.5.9. This is due to the `PMCS::action_handler()` method processing the bulk action `activate`/`deactivate` handlers without any authorization check or nonce verification. The `$_GET['snippets'][]` values are passed unsanitized to `Snippet::activate()`/`Snippet::deactivate()` which call `Snippet::update()` then `file_put_contents()` with the traversed path. This makes it possible for authenticated attackers, with Subscriber-level access and above, to overwrite arbitrary files on the server with a fixed PHP docblock content, potentially causing denial of service by corrupting critical files like `.htaccess` or `index.php`.

The weakness was shared by Phú. The advisory is shared at wordfence.com. This vulnerability is known as CVE-2026-4351 since 03/17/2026. The exploitation appears to be easy. The attack can be launched remotely. Technical details are known, but no exploit is available. MITRE ATT&CK project uses the attack technique T1006 for this issue.

Upgrading eliminates this vulnerability. The upgrade is hosted for download at perfmatters.io.

Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

Productinfo

Type

• WordPress Plugin

Name

• Perfmatters Plugin

Version

• 2.5.0
• 2.5.1
• 2.5.2
• 2.5.3
• 2.5.4
• 2.5.5
• 2.5.6
• 2.5.7
• 2.5.8
• 2.5.9

CPE 2.3info

• 🔒
• 🔒
• 🔒

CPE 2.2info

• 🔒
• 🔒
• 🔒

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Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

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