CVE-2026-4350 remediation guide
perfmatters
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-con...
A verified fixed-version field is not available. Use the linked NVD and supporting references, then confirm the vendor-supported path before changing production systems.
Identify the affected asset
Confirm whether perfmatters is installed, record the deployed version and installation path, and identify exposed interfaces.
- Record the product name, package or appliance identifier, and installed version.
- Identify internet-facing, administrative, API, and internal access paths.
- Preserve the pre-change configuration and relevant service logs.
Validate the affected-version match
Compare the deployed version with the affected range: <= 2.5.9.1. Treat incomplete inventory results as unresolved.
Prioritize with independent signals
The CVSS severity warrants an early asset and exposure review. Combine this signal with asset criticality, exposure, compensating controls, and business impact.
Apply supported remediation
Follow the vendor advisory or supported update path. Current fixed-version status: No verified fixed-version field is available yet. Preserve configuration and rollback material before change.
Verify the result
Confirm the resulting version, service health, authentication and access paths, monitoring coverage, and relevant security logs.
- Confirm the expected version and package state.
- Run a functional health check for critical service paths.
- Review authentication, error, application, and security monitoring logs.
- Reassess exposure if the supported fix cannot be applied.
Operational boundary
This page does not replace the vendor advisory, support contract, change-management process, or recovery plan. Do not infer that an asset is unaffected from an incomplete inventory query or a missing fixed-version field.