The vulnerability identified as CVE-2026-1748 affects the Invoct – PDF Invoices & Billing for WooCommerce plugin, a widely used WordPress extension for generating PDF invoices and managing billing. The root cause is a missing authorization (CWE-862) capability check on multiple plugin functions, which means that the plugin fails to verify whether an authenticated user has the necessary permissions before granting access to sensitive data. Specifically, attackers with Subscriber-level access or higher can retrieve invoice client details, invoice items, and lists of WordPress users including their email addresses. This issue exists in all versions up to and including 1.6. The vulnerability can be exploited remotely over the network without user interaction, leveraging the low privilege level of Subscriber accounts, which are commonly assigned to registered users on WordPress sites. The CVSS v3.1 base score is 4.3, reflecting a medium severity level primarily due to the confidentiality impact and ease of exploitation without user interaction. The vulnerability does not impact data integrity or system availability. No patches or official fixes have been linked yet, and no known exploits have been reported in the wild as of the publication date. The flaw exposes sensitive customer and user information, which could be leveraged for further attacks such as phishing or social engineering.

The primary impact of CVE-2026-1748 is unauthorized disclosure of sensitive data, including invoice details and user email addresses. This can lead to privacy violations, regulatory compliance issues (e.g., GDPR), and reputational damage for organizations using the affected plugin. Attackers gaining access to invoice and user data could conduct targeted phishing campaigns or identity theft. Although the vulnerability does not allow modification or deletion of data, the exposure of confidential business and customer information can undermine trust and potentially lead to financial losses. Since the exploit requires only Subscriber-level access, which is commonly granted to registered users or customers, the attack surface is broad. Organizations with WooCommerce stores using this plugin are at risk, especially those handling sensitive billing information. The lack of known exploits in the wild reduces immediate risk but does not eliminate the threat, as attackers may develop exploits in the future. Overall, the vulnerability poses a moderate risk to confidentiality and privacy, with no direct impact on system integrity or availability.

To mitigate this vulnerability, organizations should first check for and apply any official patches or updates released by the plugin vendor once available. In the absence of patches, administrators should restrict Subscriber-level user capabilities to the minimum necessary, potentially disabling or limiting access to the affected plugin functions. Implementing strict role-based access controls (RBAC) and auditing user permissions can reduce exposure. Additionally, monitoring logs for unusual access patterns to invoice or user data endpoints can help detect exploitation attempts. If feasible, temporarily disabling the Invoct plugin until a fix is released may be warranted for high-risk environments. Web application firewalls (WAFs) can be configured to block suspicious requests targeting the vulnerable functions. Educating users about phishing risks stemming from leaked email addresses is also advisable. Finally, organizations should maintain regular backups and ensure their WordPress and WooCommerce installations are kept up to date to reduce overall attack surface.