Vulnerability Description
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`.
CVSS Score
HIGH
Related Weaknesses (CWE)
References
- https://perfmatters.io/docs/changelog/
- https://www.wordfence.com/threat-intel/vulnerabilities/id/c172ab2b-ce1f-4a0d-b31
FAQ
What is CVE-2026-4351?
CVE-2026-4351 is a vulnerability with a CVSS score of 8.1 (HIGH). 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 proces...
How severe is CVE-2026-4351?
CVE-2026-4351 has been rated HIGH with a CVSS base score of 8.1/10. Review the CVSS metrics above for detailed severity breakdown.
Is there a patch for CVE-2026-4351?
Check the references section above for vendor advisories and patch information. Review vendor security bulletins for remediation guidance.