CVE-2026-18391 — CRITICAL (9.8)

Vulnerability Description

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.

CVSS Score

9.8

CRITICAL

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Attack Vector

NETWORK

Attack Complexity

LOW

Privileges Required

NONE

User Interaction

NONE

Scope

UNCHANGED

Confidentiality

HIGH

Integrity

HIGH

Availability

HIGH

Related Weaknesses (CWE)

CWE-434

References

https://wpscan.com/vulnerability/191f76cf-e5bd-4a37-ac1c-9187cea2aa27/

FAQ

What is CVE-2026-18391?

CVE-2026-18391 is a vulnerability with a CVSS score of 9.8 (CRITICAL). 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 Injectio...

How severe is CVE-2026-18391?

CVE-2026-18391 has been rated CRITICAL with a CVSS base score of 9.8/10. This is considered a critical vulnerability requiring immediate attention.

Is there a patch for CVE-2026-18391?

Check the references section above for vendor advisories and patch information. Review vendor security bulletins for remediation guidance.