Hundreds of thousands of FortiGate firewalls are vulnerable to a critical security issue identified as CVE-2023-27997, almost a month after Fortinet released an update that addresses the problem.

CVE-2023-27997 is exploitable and allows an unauthenticated attacker to execute code remotely on vulnerable devices with the SSL VPN interface exposed on the web.

Offensive security solutions company Bishop Fox reported on Friday that despite the calls to patch, more than 300,000 FortiGate firewall appliances are still vulnerable to attacks and reachable over the public internet.

The query above showed 489,337 devices but not all of them were vulnerable to CVE-2023-27997, also referred to as Xortigate.

Another discovery Bishop Fox researchers made was that many of the exposed FortiGate devices did not receive an update for the past eight years, some of them running FortiOS 6, which reached end of support last year on September 29.

These devices are vulnerable to several critical-severity flaws that have proof-of-concept exploit code publicly available.