CVE-2024-21762 and CVE-2024-23113: Multiple Critical Vulnerabilities in Fortinet, One Likely Under Active Exploitation

On 8 February 2024 FortiGuard disclosed two critical FortiOS vulnerabilities (CVE-2024-23113 — format string; CVE-2024-21762 — out-of-bounds write) that could allow unauthenticated actors to execute arbitrary code; FortiGuard is aware of potential exploitation for CVE-2024-21762 though no public PoC has been identified. Arctic Wolf recommends upgrading affected FortiOS and FortiSIEM versions to the listed fixed releases and provides temporary mitigations (remove fgfm access for CVE-2024-23113, disable SSL VPN for CVE-2024-21762).