CVE-2026-41940

CVE-2026-41940 is a critical missing-authentication flaw (CWE-306) in the login flow of WebPros cPanel & WHM (versions after 11.40) and WP2 (WordPress Squared) that lets unauthenticated remote attackers bypass authentication and gain unauthorized access to the control panel. Because no privileges, user interaction, or special conditions are required, any attacker who can reach the login endpoint over the network can attempt it. Beyond control-panel account takeover, public proofs of concept — including watchTowr's 'AuthBypass to RCE' exploit — show the flaw can be chained to remote code execution, and reporting indicates a single hosting customer could obtain root control of an entire shared server. Any hosting provider, MSP, reseller, or organization running cPanel/WHM or WP Squared is affected; cPanel is the dominant commercial hosting control panel, implying a very large installed base of shared-hosting servers and hosted domains. Exploitation is confirmed in the wild: CISA added it to the KEV on 2026-04-30 with known ransomware use, EPSS assigns a 98.5% probability of exploitation within 30 days (100th percentile), and multiple threat actors are actively exploiting it, including against government and MSP networks.

What to do: Patch immediately per WebPros' advisory — the source data does not specify fixed version numbers, so follow vendor instructions for exact patched releases; CISA KEV/BOD 22-01 requires federal agencies to apply mitigations or discontinue use by the stated deadline (reported as Sunday). Until patched, restrict access to the cPanel/WHM login interface (IP allowlisting, VPN, or limiting management-interface exposure) and hunt for indicators of compromise such as unexpected control-panel logins, new admin accounts, webshells, or ransomware artifacts. The referenced public PoCs can be used to validate whether your instances are exploitable.