FortiOS
CVE-2023-27997: FortiOS and FortiProxy SSL-VPN Heap-Based Buffer Overflow
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.
Published
Automatic summary from the vendor's CVE record. We haven't written a full analysis of this vulnerability yet.
Affected and fixed versions
| Product / branch | Fixed in |
|---|---|
| FortiOS-6K7K 7.0 | 7.0.12 or later |
| FortiOS-6K7K 7.0 | 7.0.12 or later |
| FortiOS-6K7K 6.4 | 6.4.13 or later |
| FortiOS-6K7K 6.4 | 6.4.13 or later |
| FortiOS-6K7K 6.4 | 6.4.13 or later |
| FortiOS-6K7K 6.4 | 6.4.13 or later |
| FortiOS-6K7K 6.4 | 6.4.13 or later |
| FortiOS-6K7K 6.2.9 to 6.2.13 | 6.2.15 or later |
| FortiOS-6K7K 6.2.6 to 6.2.7 | 6.2.15 or later |
| FortiOS-6K7K 6.2 | 6.2.15 or later |
| FortiOS-6K7K 6.0.12 to 6.0.16 | 6.0.17 or later |
| FortiOS-6K7K 6.0 | 6.0.17 or later |
| FortiProxy 7.2.0 to 7.2.3 | 7.2.4 or later |
| FortiProxy 7.0.0 to 7.0.9 | 7.0.10 or later |
| FortiProxy 2.0.0 to 2.0.12 | Upgrade past 2.0.12; see the advisory |
| FortiProxy 1.2.0 to 1.2.13 | Upgrade past 1.2.13; see the advisory |
| FortiProxy 1.1.0 to 1.1.6 | Upgrade past 1.1.6; see the advisory |
| FortiOS 7.2.0 to 7.2.4 | 7.2.5 or later |
| FortiOS 7.0.0 to 7.0.11 | 7.0.12 or later |
| FortiOS 6.4.0 to 6.4.12 | 6.4.13 or later |
| FortiOS 6.2.0 to 6.2.13 | 6.2.14 or later |
| FortiOS 6.0.0 to 6.0.16 | 6.0.17 or later |
Always confirm against the vendor advisory, which lists every fixed hotfix.
What it is
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.
Exploitation
CISA lists this CVE as exploited in the wild since 13 Jun 2023, including in ransomware campaigns.
Sources
KEV status, EPSS score and vendor data refreshed automatically, last on 10 Oct 2026.