CVE-2026-18391: WooCommerce Subscriptions < 9.1.0 - Unauthenticated RCE via PHP Object Injection
The WooCommerce Subscriptions WordPress plugin before 9.1.0 does not validate user input before unserializing it on stores with High-Performance Order Storage enabled, leading to a PHP Object Injection issue which unauthenticated users can escalate to Remote Code Execution via a gadget chain present in the bundled dependencies.
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Upgrade
Upgrade
woocommerce/woocommerce-subscriptionsto a version that resolves this vulnerability.Fixed in 9.1.0
Event History
Frequently Asked Questions
What is the severity of CVE-2026-18391?
CVE-2026-18391 has a severity score of 91 indicating a critical risk level.
How do I fix CVE-2026-18391?
To fix CVE-2026-18391, update the WooCommerce Subscriptions plugin to version 9.1.0 or later.
What is CVE-2026-18391?
CVE-2026-18391 is a vulnerability in the WooCommerce Subscriptions plugin allowing unauthenticated Remote Code Execution via PHP Object Injection.
Who is affected by CVE-2026-18391?
Users of the WooCommerce Subscriptions WordPress plugin prior to version 9.1.0 with High-Performance Order Storage enabled are affected by CVE-2026-18391.
What type of vulnerability is CVE-2026-18391?
CVE-2026-18391 is classified as a Code Injection vulnerability.