WordPress Critical · CVSS 9.8 CVE-2026-18143 September 26, 2026

Request a Quote for WooCommerce: arbitrary file upload

Request a Quote for WooCommerce

Arbitrary file upload in the Request a Quote for WooCommerce component. Threat level: Critical (CVSS 9.8).

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Who is affected

This vulnerability affects: Request a Quote for WooCommerce. If you use this component on your site, check the version and update it as soon as possible.

How dangerous

Rating: Critical, CVSS 9.8 out of 10. Critical flaws are often exploited en masse within hours of disclosure.

What this flaw is

Arbitrary file upload lets an attacker place their own file on the server, most often a PHP script (a web shell) that gives them remote control of the site.

It is a short path from a single flaw to a full site takeover and persistent, hidden access.

Score breakdown (CVSS vector)

What the CVSS 9.8 rating means in practice:

  • The attack can be carried out remotely, over the internet.
  • No login or account required.
  • Requires no action from the victim.
  • At risk: data confidentiality, integrity (data can be altered), site availability.

Weakness class: CWE-434.

How to fix: arbitrary file upload

  • Update the component to the version that closes the upload flaw.
  • Scan wp-content/uploads for files that are not media, above all any .php, .phtml or double-extension files (e.g. image.php.jpg), and remove web shells.
  • Block execution of PHP inside the uploads directory at the server level (.htaccess / nginx rule).
  • Rotate admin and database passwords and the wp-config.php salts after cleanup.
  • If a shell was already placed, treat the site as compromised and restore from a clean backup.

Prefer not to do this yourself? We will handle the update, check for signs of a break-in and secure the site. Write to us →

Frequently asked questions

Does this vulnerability affect my site?

It affects sites that use Request a Quote for WooCommerce. Check whether you have this component installed and which version, the flaw only applies to the vulnerable version range. You can verify it in under a minute with our free vulnerability scanner.

How do I check whether I have the vulnerable version?

In your admin panel (in WordPress: Plugins / Themes) check the installed version of Request a Quote for WooCommerce and compare it with the vendor advisory that names the fixed version. If it is lower, or you are not sure, run our scanner, which reads the versions visible in the site code.

How urgently should I react?

This is a Krytyczna-severity flaw, so treat it as urgent, high-impact vulnerabilities are often exploited automatically within hours of disclosure. Update as soon as possible.

What if a patch is not available yet?

Until a fix ships, reduce the exposure: temporarily disable the vulnerable component, restrict access to the affected functionality, or add a WAF rule blocking the vulnerable request. Keep a current off-site backup and watch for signs of a break-in.

Is updating alone enough?

If the site has not been attacked yet, updating to the patched version closes the hole. If there are already signs of compromise (unknown files, new admin accounts, redirects), the update does not undo the break-in, you also need to clean the site and rotate passwords and the WordPress salts.

Do not guess, check

Does this flaw affect your site?

We will run a free audit: we check versions, plugins, and configuration, and tell you plainly whether you are safe.

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