CVE-2023-27997
Fortinet FortiOS and FortiProxy SSL-VPN contain a heap-based buffer overflow vulnerability which can allow an unauthenticated, remote attacker to execute code or commands via specifically crafted requests.
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.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H- fortiguard.com/psirt/FG-IR-23-097Vendor Advisory
- cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2023-27997US Government Resource
Actively exploited and used by ransomware crews. Patch immediately.
- Exploitation
- Confirmed in the wild (CISA KEV)
- Federal remediation deadline
- Overdue by 1210 days
- Ransomware
- Used in known ransomware campaigns
- CVSS
- 9.8 CRITICAL
- EPSS (30-day exploit probability)
- 85.7% · top 1% of all CVEs
- Weakness
- CWE-122
- Attack vector
- Network, remotely reachable
- Preconditions
- No privileges and no user interaction
- 1.Apply updates per vendor instructions.
- 2.Treat as emergency change: patch or isolate internet-facing instances first.
- 3.Review exposure: confirm which instances are reachable from the internet and restrict access until patched.
- 4.Hunt for compromise: review logs for the disclosure window, not just from the patch date.
- 5.Verify offline/immutable backups and segment the affected systems. This flaw is used for ransomware initial access.
Assessment is derived automatically from the live signals above; verify against your own asset inventory.