Exploited CVEs / Fortinet / CVE-2023-27997
CVE-2023-27997
Actively exploited Fortinet FortiOS and FortiProxy SSL-VPN vulnerability, Critical severity, CVSS 9.8. Added to the CISA KEV catalog 2023-06-13.
All about CVE-2023-27997: the Senserva AI read, the CISA required action and deadline, the official fix, and the questions admins ask.
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Fortinet FortiOS and FortiProxy SSL-VPN Heap-Based Buffer Overflow Vulnerability. Exploitation in the wild is confirmed by CISA, not predicted, and the vulnerability is known to be used in ransomware campaigns. Federal agencies were required to remediate by 2023-07-04 (that deadline has passed); treat that date as the outer bound for your own environment. The fix is in the vendor advisory: Fortinet PSIRT Advisories, linked below.
Risk summary
Senserva AI Opinion for CVE-2023-27997
Reachable pre-authentication over the SSL-VPN interface, this Fortinet FortiOS and FortiProxy heap overflow lets remote attackers execute code on the firewall itself, and it carries Critical Severity (CVSS 9.8), 86% EPSS, and confirmed ransomware use. SSL-VPN portals must face the internet to do their job, which puts the vulnerable surface in front of every scanner on earth. CISA listed it in June 2023.
Do this: Upgrade FortiOS and FortiProxy now, and if SSL-VPN is unused on a device, disable the interface entirely.
AI-generated from public data, 2026-07-07. Verify against the vendor advisory before acting.
Senserva AI Opinion and rich prompt for CVE-2023-27997
Copy this prompt into Claude, ChatGPT, or Copilot. The facts are included, sourced from this page.
Full tracking and change history for CVE-2023-27997
Published and last-revised dates are authoritative, from Microsoft MSRC (or the CISA KEV date-added). Senserva additionally records day-to-day changes from 2026-07-07, refreshed several times a day; the change count reflects that forward-only tracking.
CISA required action
Federal (BOD 22-01) remediation due date: 2023-07-04 (past due).
Apply updates per vendor instructions.
Official fix for CVE-2023-27997
The authoritative fix and affected-version list are published by the vendor. Find the FortiOS and FortiProxy SSL-VPN advisory on Fortinet PSIRT Advisories.
Common questions about CVE-2023-27997
Is CVE-2023-27997 actively exploited?
Yes. CVE-2023-27997 was added to the CISA Known Exploited Vulnerabilities (KEV) catalog on 2023-06-13, which means exploitation in the wild has been confirmed, not predicted. Its EPSS 30-day exploitation probability is 86%. CISA also reports it is known to be used in ransomware campaigns.
What is the CISA deadline and required action for CVE-2023-27997?
CISA set the federal (BOD 22-01) remediation due date at 2023-07-04, which has passed; treat any unremediated system as overdue. The verbatim required action: Apply updates per vendor instructions.
What fixes CVE-2023-27997?
The authoritative fix is in the vendor advisory: see Fortinet PSIRT Advisories for the patched FortiOS and FortiProxy SSL-VPN versions and any workarounds. KEV listing makes this a fix-first item: patch it ahead of higher-CVSS issues nobody is exploiting.
Can I ask my own AI about CVE-2023-27997?
Yes. This page includes a free, ready-to-paste AI prompt containing CVE-2023-27997's key facts: severity, CVSS, EPSS, the KEV date, the CISA due date, and the required action. Copy it into Claude, ChatGPT, or Copilot; the data is refreshed three times a day (5 AM, 12:30 PM, and 7 PM US Central).
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Authoritative references
Every actively exploited CVE, searchable with due dates and CSV export: the exploited-CVE tracker. The newest additions: exploited this week.
