What’s Vulnerable › Vulnerabilities

CVE-2026-4351: Perfmatters <= 2.5.9 - Authenticated (Subscriber+) Arbitrary File Overwrite via 'snippets' Parameter

• Severity: high (CVSS 8.1 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.4% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-04-10 · updated 2026-06-17
• Weakness: CWE-22

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`.

Affected products

• Perfmatters: through 2.5.9

References

• https://perfmatters.io/docs/changelog/
• https://www.wordfence.com/threat-intel/vulnerabilities/id/c172ab2b-ce1f-4a0d-b31f-b75ff2f03506?source=cve

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