VulnTideExploited vulnerabilities, by vendor. Data as of .
Known exploitedIn CISA's KEV catalog since Ransomware use: known
Fortinet FortiOS and FortiProxy SSL-VPN

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

Is it exploited?

Yes. CISA added it to the Known Exploited Vulnerabilities catalog on , the same day the CVE record was published.

How likely is exploitation in the next 30 days?
85.7%

EPSS score, percentile 99.7 of all scored records

How severe?
9.2 Critical

CVSS v3.1 base score, given by the CNA

What should I do?

CISA deadline . Apply updates per vendor instructions.

The CVE record links no vendor advisory, patch or mitigation.

Which versions are affected?

Affected

  • 7.0.10
  • 7.0.5
  • 6.4.12
  • 6.4.10
  • 6.4.8
  • 6.4.6

and 16 more in the table below

Versions by product

Source: CISA Known Exploited Vulnerabilities (KEV) catalog, 2026.10.28, as of ; FIRST Exploit Prediction Scoring System (EPSS), v2026.06.15, as of ; CVE List V5 (CVE Program), cve_2026-10-28_0000Z, as of . About the data.

What to do

Required action, set by CISA

Apply updates per vendor instructions.

CISA due date for this action: .

Solution (from the CVE record)

Please upgrade to FortiOS-6K7K version 7.0.12 or above Please upgrade to FortiOS-6K7K version 6.4.13 or above Please upgrade to FortiOS-6K7K version 6.2.15 or above Please upgrade to FortiOS-6K7K version 6.0.17 or above Please upgrade to FortiProxy version 7.2.4 or above Please upgrade to FortiProxy version 7.0.10 or above Please upgrade to FortiOS version 7.4.0 or above Please upgrade to FortiOS version 7.2.5 or above Please upgrade to FortiOS version 7.0.12 or above Please upgrade to FortiOS version 6.4.13 or above Please upgrade to FortiOS version 6.2.14 or above Please upgrade to FortiOS version 6.0.17 or above

Advisories and patches

The CVE record links no vendor advisory, patch or mitigation.

Linked from CISA's catalog entry

Affected products and versions

As listed in the CVE record.

Fortinet FortiOS-6K7K
StatusVersions
Affected7.0.10
Affected7.0.5
Affected6.4.12
Affected6.4.10
Affected6.4.8
Affected6.4.6
Affected6.4.2
Affected6.2.9 through 6.2.13
Affected6.2.6 through 6.2.7
Affected6.2.4
Affected6.0.12 through 6.0.16
Affected6.0.10

Versions not listed are: unaffected.

Fortinet FortiProxy
StatusVersions
Affected7.2.0 through 7.2.3
Affected7.0.0 through 7.0.9
Affected2.0.0 through 2.0.12
Affected1.2.0 through 1.2.13
Affected1.1.0 through 1.1.6

Versions not listed are: unaffected.

Fortinet FortiOS
StatusVersions
Affected7.2.0 through 7.2.4
Affected7.0.0 through 7.0.11
Affected6.4.0 through 6.4.12
Affected6.2.0 through 6.2.13
Affected6.0.0 through 6.0.16

Versions not listed are: unaffected.

Source: CVE List V5 (CVE Program), cve_2026-10-28_0000Z, as of . About the data.

About this vulnerability

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.

Summary: CISA's KEV catalog, as of .

  • CISA added CVE-2023-27997 to its Known Exploited Vulnerabilities (KEV) catalog on 13 Jun 2023.
  • CISA marks it as known to be used in ransomware campaigns.
  • The due date CISA sets for the required action is 4 Jul 2023.
  • The CVE record was published on 13 Jun 2023, the same day it was added to KEV.
  • The CVE record carries a CVSS v3.1 base score of 9.2 (Critical), given by its CNA.
  • FIRST's EPSS model puts the probability of exploitation in the next 30 days at 85.7% (percentile 99.7), as of 28 Oct 2026.
  • CISA's SSVC assessment in the CVE record: exploitation active, automatable yes, technical impact total.

Source: CISA Known Exploited Vulnerabilities (KEV) catalog, 2026.10.28, as of ; CVE List V5 (CVE Program), cve_2026-10-28_0000Z, as of ; FIRST Exploit Prediction Scoring System (EPSS), v2026.06.15, as of . About the data.

Description

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.

Source: CVE List V5 (CVE Program), cve_2026-10-28_0000Z, as of . About the data.

Weakness

CWE and CAPEC are maintained by MITRE; the entries are those named in the CVE record and the KEV entry.

Timeline

DateEvent
CVE record published
Added to CISA KEV
CISA due date for the required action
CVE record last updated

References

More exploited Fortinet vulnerabilities

  • CVE-2025-61624: Fortinet Multiple Products Path Traversal Vulnerability (added )
  • CVE-2026-104286: Fortinet FortiMail Path Traversal Vulnerability (added )
  • CVE-2025-25249: Fortinet Multiple Products Heap-based Buffer Overflow Vulnerability (added )
  • CVE-2025-68686: Fortinet FortiOS Exposure of Sensitive Information to an Unauthorized Actor Vulnerability (added )
  • CVE-2026-25089: Fortinet FortiSandbox OS Command Injection Vulnerability (added )
  • CVE-2026-39808: Fortinet FortiSandbox OS Command Injection Vulnerability (added )