CVE-2023-27997: Fortinet FortiOS and FortiProxy SSL-VPN Heap-Based Buffer Overflow Vulnerability

Critical severity, CVSS 9.8. Actively exploited: in CISA KEV since 2023-06-13. EPSS: 85.7% chance of exploitation in the next 30 days.

A heap-based buffer overflow vulnerability [CWE-122] in FortiOS version 7.2.4 and below, version 7.0.11 and below, version 6.4.12 and below, version 6.0.16 and below and FortiProxy version 7.2.3 and below, version 7.0.9 and below, version 2.0.12 and below, version 1.2 all versions, version 1.1 all versions SSL-VPN may allow a remote attacker to execute arbitrary code or commands via specifically crafted requests.

Affected products

• Fortinet FortiOS: from 6.0.0, up to and including 6.0.16; from 6.2.0, up to and including 6.2.13; from 6.4.0, up to and including 6.4.12; from 7.0.0, up to and including 7.0.11; from 7.2.0, up to and including 7.2.4; from 6.0.12, up to and including 6.0.16; …
• Fortinet FortiProxy: from 1.1.0, up to and including 1.1.6; from 1.2.0, up to and including 1.2.13; from 2.0.0, up to and including 2.0.12; from 7.0.0, up to and including 7.0.9; from 7.2.0, up to and including 7.2.3

Published 2023-06-13. Last modified 2026-07-31.