Critical Vulnerabilities Patched in WHMCS Billing Software for Hosting Providers
WebPros International has disclosed two serious vulnerabilities in its WHMCS billing management platform used by hosting and cloud service providers. CVE-2026-67399 allows unauthenticated remote code execution through unsafe deserialization of untrusted data under specific conditions, potentially compromising the entire server environment and associated data. CVE-2026-67398 affects the 2CheckOut payment gateway module and stems from missing authorization checks, enabling attackers to retrieve sensitive customer information including names, addresses, emails, and phone numbers without authentication. HackerOne assigned CVSS v4.0 scores of 9.3 (Critical) to the first issue and 8.2 (High) to the second. WebPros released fixed versions WHMCS 9.0.8 and 8.13.7, and recommended disabling the 2CheckOut module as a temporary mitigation for the second flaw.
Security NEXTSep 15, 2026Translated from Japanese