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Vulnerabilities

Vulnerability · CVE-2023-27997

Fortinet FortiOS and FortiProxy SSL-VPN Heap-Based Buffer Overflow Vulnerability

Published Jun 12, 2023 · catalog updated Jul 30, 2026 · Fortinet FortiOS and FortiProxy

Patch now

CVE-2023-27997 is in the CISA known-exploited catalog, due Jul 4, 2023. Confirm Fortinet FortiOS and FortiProxy against the vendor advisory and apply that fix. The CVSS score does not change the priority.

Gaps on this record

  • No version range is stored. A customer cannot check an installed version against this record.
Severity
Critical9.8
Known exploitation
CISA KEV and VulnCheck KEV
EPSS
85.69%
Remediation
Remediation guidance
Affected products
cpe fortinet/fortios · cpe fortinet/fortiproxy · vendor Fortinet FortiOS and FortiProxy · vendor Fortinet FortiOS and FortiProxy SSL-VPN

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.

Are you affected?

Enter the version you run. The result uses only the ranges stored on this record.

The check returns affected, not affected, or incomplete. It does not guess a version that is missing from the record.

  • cpe fortinet/fortiosversion unspecified
  • cpe fortinet/fortiproxyversion unspecified
  • vendor Fortinet FortiOS and FortiProxyversion unspecified
  • vendor Fortinet FortiOS and FortiProxy SSL-VPNversion unspecified

How to fix CVE-2023-27997

What to do

Three questions, each answered from this record only. Confirm the vendor advisory before you patch.

Should you patch?

CVE-2023-27997 is in the CISA known-exploited catalog, due Jul 4, 2023. Confirm Fortinet FortiOS and FortiProxy against the vendor advisory and apply that fix. The CVSS score does not change the priority.

Which versions are affected?

Affected version ranges are not on this record. Apply updates per vendor instructions.

What should an analyst verify?

CWE-122: Heap-based Buffer Overflow; CWE-787: Out-of-bounds Write. EPSS 85.69%. The CISA KEV listing is the exploitation evidence. No Exploit-DB or Metasploit reference is linked. Use the source links for the original advisory.

Technology hubs

Fortinet security

Code

The project this record applies to. Exploit listings stay in References.

No public source repository is identified for this product.

Timeline

Detection, updates, and resolution for this record.

  1. Jun 13, 2023 · Catalog

    Detected

    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 c

  2. Jun 13, 2023 · CISA KEV

    Known exploited

    Apply updates per vendor instructions.

  3. Jul 4, 2023 · CISA KEV

    Remediation due

    Apply updates per vendor instructions.

  4. Jul 30, 2026 · Catalog

    Updated

    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 c

Sources

  • CISA KEVConfirmed exploitationCVE-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.

    cisa.gov
  • CVE.orgVulnerability recordCVE-2023-27997

    Official CVE identifier

    cve.org
  • FIRST EPSSExploitation probabilityCVE-2023-27997

    30-day exploitation probability 85.7%

    first.org
  • NIST NVDVulnerability recordCVE-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 version

    nvd.nist.gov
  • VulnCheck KEVConfirmed exploitationCVE-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.

    vulncheck.com

References

Freshness

Last verified in this catalog Oct 17, 2026. Significant claims (KEV, EPSS, CVSS, affected ranges) come from the source rows above — open the original publisher for the authoritative advisory.