CVE-2023-27997 — Fortinet Fortios

As of 2025-10-24, CVE-2023-27997 is a CRITICAL-severity vulnerability in Fortinet Fortios, CVSS v3.1 9.8, EPSS 90.9% (99.6th percentile). It is listed in the CISA Known Exploited Vulnerabilities catalog (added 2023-06-13), with a US federal remediation deadline of 2023-07-04, and CISA links it to known ransomware campaigns. Threadlinqs Intelligence links 6 tracked threat campaigns to CVE-2023-27997, most recently “Cyble H1 2026 Threat Actor Landscape: 261 Tracked Groups, Five Most Active Actors Profiled”.

Last updated: 2025-10-24

What is CVE-2023-27997?

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.

The record classifies CVE-2023-27997 under weakness classes CWE-122, CWE-787. Its CVSS v3 base vector states that the flaw is reachable remotely over the network, needs no prior authentication, needs no user interaction, and has high impact on confidentiality, integrity, availability. 15 affected-product entries are recorded, across 1 vendor, listed below. The identifier was first published 1187 days ago.

Severity and exploitation probability

CVSS v3.1 base score

9.8 — CRITICAL
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

EPSS (FIRST)

90.9% probability of exploitation in the next 30 days, higher than 99.6% of all scored CVEs

CISA KEV

Listed since 2023-06-13, federal remediation deadline 2023-07-04 — used in known ransomware campaigns

Threadlinqs priority

10/10 — CISA lists it as used in ransomware, which Threadlinqs scores at the maximum

Published

2023-06-13, last modified 2025-10-24

Is CVE-2023-27997 being exploited?

CISA added CVE-2023-27997 to the Known Exploited Vulnerabilities catalog on 2023-06-13, which means the agency holds evidence of exploitation in the wild; US federal civilian agencies had to remediate it by 2023-07-04 under BOD 22-01. CISA flags the vulnerability as one used in known ransomware campaigns. It currently carries a trending score of 40 in the Threadlinqs vulnerability feed.

Affected products and versions

• Fortinet: Fortios, Fortios 6.2.4, Fortios 7.0.5, Fortios 6.2.6, Fortios 6.4.10, Fortiproxy, Fortios 6.2.7, Fortios 6.4.12, Fortios 6.0.10, Fortios 6.4.6, Fortios 6.4.8, Fortios 6.4.2, Fortios 7.0.10, Fortigate 6000, Fortigate 7000

How to fix CVE-2023-27997

The record marks a vendor fix as available for CVE-2023-27997. Vendor advisory: https://fortiguard.com/psirt/FG-IR-23-097. Because CVE-2023-27997 is KEV-listed, US federal civilian agencies were required to apply the vendor fix, or stop using the product, by 2023-07-04. Apply the vendor fix referenced above to every affected product listed in this record, then confirm the running version against the vendor advisory.

Threat activity tracking CVE-2023-27997

6 tracked threats in the Threadlinqs corpus reference CVE-2023-27997, either in the campaign’s CVE list or as an indicator on the campaign record.

• Cyble H1 2026 Threat Actor Landscape: 261 Tracked Groups, Five Most Active Actors Profiled — HIGH · 2026-07-27
• Sen. Wyden Urges Binding Federal Mandate to Purge Internet-Facing Legacy VPNs for Zero-Trust Remote Access — MEDIUM · 2026-07-27
• FortiBleed: Mass Credential Compromise Campaign Against Internet-Exposed Fortinet FortiGate Devices (86,644 Devices, 194 Countries) — CRITICAL · 2026-07-11
• FortiBleed Credential Theft Campaign Linked to INC and Lynx Ransomware Operations — CRITICAL · 2026-07-05
• FortiBleed Credential Theft Campaign: FortigateSniffer Tool Deployed Against 430,000+ FortiGate Firewalls, Linked to INC Ransom and Lynx Ransomware — CRITICAL · 2026-07-01
• Kyber Ransomware: Post-Quantum Hybrid Encryption Operation Targeting Windows & VMware ESXi — CRITICAL · 2026-04-22

Sources

Seeded from nvd and not yet processed by the Threadlinqs enrichment pipeline, so blank CVSS, EPSS or KEV fields above mean NOT MEASURED rather than measured-absent.

• fortiguard.com

← all vulnerabilities · Markdown version · Threadlinqs Intelligence