Check Point released an emergency fix on Monday for a critical authentication bypass vulnerability affecting its Remote Access VPN and Mobile Access deployments - but attackers, including ransomware criminals, got a month-long head start. Attacks against the bug, tracked as CVE-2026-50751, began on May 7, according to Check Point VP of research Lotem Finkelstein, and picked up in early June. The security software vendor spotted suspicious activity and began investigating the zero-day on June 4, Finkelstein said in a Monday blog. “We have observed indications that exploitation has been limited to a relatively small number of targeted organizations (several dozen globally), primarily over the past few days,” Finkelstein wrote, adding that, in at least one case, investigators observed post-compromise activity associated with a Qilin ransomware affiliate. This same ransomware scum is also likely exploiting other VPN-related vulnerabilities in Palo Alto Networks, Fortinet, and F5 products, Finkelstein said. CVE-2026-50751 is due to a logic-flow weakness in the Remote Access and Mobile Access certificate validation process, and it allows remote attackers to bypass authentication and establish a remote access VPN connection without a user password. It affects Mobile Access/SSL VPNs, Remote Access VPNs, and Spark Firewalls configured to use the deprecated IKEv1 key exchange protocol. While investigating CVE-2026-50751 and affected VPN components, Check Point found another vulnerability, CVE-2026-50752, in its Security Gateways and Spark Firewall products. It’s due to a bug in the certificate validation logic of the deprecated IKEv1 key exchange method, and can lead to man-in-the-middle attacks on the VPN site-to-site configuration. Check Point says that it hasn’t received any reports of in-the-wild exploitation of CVE-2026-50752. Check Point urges customers running vulnerable gateways and firewalls to apply the hotfixes, and the vendor also provided alternative mitigation options with instructions in the security advisories. The software provider also published a list of indicators of compromise, including attacker IPs, and recommends customers search Check Point SmartConsole logs for possible VPN certificate authentication attempts associated with observed attacker infrastructure and certificate subject names for at least May 7 through June 5. ®