Risk Letters

Exploited vulnerability

CVE-2026-18391

TLP:CLEAR

Unrestricted Upload of File with Dangerous Type

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.

Facts

  • Vendor: WooCommerce
  • Product: WooCommerce Subscriptions
  • EPSS (probability of exploitation within 30 days): 1 %
  • First known exploitation: 13 October 2026
  • First seen by Risk Letters: 13 October 2026

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Data: NVD (public domain), CISA KEV, FIRST EPSS, MITRE ATT&CK, AlienVault OTX. NVD