CVE-2025-66071 identifies a missing authorization vulnerability in the Custom Order Numbers for WooCommerce plugin developed by tychesoftwares, affecting all versions up to and including 1.11.0. This vulnerability arises from improperly configured access control mechanisms that fail to restrict unauthorized users from performing certain actions related to custom order numbers. Specifically, the flaw allows remote attackers to manipulate order number data without requiring any authentication or user interaction, as indicated by the CVSS vector (AV:N/AC:L/PR:N/UI:N). While the vulnerability does not impact confidentiality or availability, it compromises data integrity by enabling unauthorized modification of order numbers, which are critical for order tracking, auditing, and reconciliation in e-commerce environments. The vulnerability was published on November 21, 2025, with a CVSS v3.1 base score of 5.3, categorized as medium severity. No known exploits have been reported in the wild, and no official patches have been linked yet, though the vendor is expected to release updates to address the issue. The vulnerability affects the WooCommerce ecosystem, widely used in online retail, and could be exploited by attackers to disrupt business operations or facilitate fraud by altering order identifiers.

For European organizations, this vulnerability poses a risk primarily to the integrity of e-commerce order data. Unauthorized modification of order numbers can lead to discrepancies in order processing, financial reconciliation errors, and potential exploitation for fraudulent activities such as order duplication or manipulation of transaction records. This can undermine customer trust and complicate compliance with financial and data integrity regulations such as GDPR, which mandates accurate record-keeping. The impact is particularly significant for medium to large e-commerce businesses relying on WooCommerce and this plugin for order management. While the vulnerability does not directly expose sensitive customer data or cause service outages, the integrity compromise can have downstream effects on business operations, auditing, and legal compliance. Given the plugin’s role in customizing order numbers, attackers could exploit this flaw to create confusion in order fulfillment or to mask fraudulent transactions, increasing operational risk.

Organizations should immediately audit their WooCommerce installations to identify if the Custom Order Numbers for WooCommerce plugin is in use and verify the version. Until an official patch is released, restrict administrative access to the plugin’s configuration and order management interfaces to trusted personnel only. Implement strict role-based access controls (RBAC) to limit who can modify order numbers or related settings. Monitor order number changes for anomalies or unexpected patterns that could indicate exploitation attempts. Consider implementing additional logging and alerting on order number modifications to detect unauthorized activity promptly. Engage with the plugin vendor or community to obtain updates or patches as soon as they become available and apply them promptly. Additionally, review and strengthen overall WooCommerce security posture, including ensuring the platform and all plugins are regularly updated and that security best practices for web applications are followed. For critical e-commerce operations, consider compensating controls such as manual verification steps in order processing workflows to detect irregularities caused by unauthorized order number changes.