Fortinet FortiOS Default Configuration Vulnerability

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• cpe fortinet/fortiosversion unspecified
• vendor Fortinet FortiOSversion unspecified

How to fix CVE-2019-5591

• Recommended remediation

  Apply updates per vendor instructions. CISA due date May 3, 2022.

• Official advisories

  • CISA KEV · cisa.gov
  • CVE.org · cve.org
  • FIRST EPSS · first.org
  • NIST NVD · nvd.nist.gov
  • VulnCheck KEV · vulncheck.com

What to do

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

Technology hubs

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. Aug 14, 2020 · Catalog

   Detected

   Fortinet FortiOS contains a default configuration vulnerability that may allow an unauthenticated attacker on the same subnet to intercept sensitive information by impersonating the Lightweight Directory Access Protocol (LDAP) server.

2. Nov 3, 2021 · CISA KEV

   Known exploited

   Apply updates per vendor instructions.

3. May 3, 2022 · CISA KEV

   Remediation due

   Apply updates per vendor instructions.

4. Aug 14, 2026 · Catalog

   Updated

   Fortinet FortiOS contains a default configuration vulnerability that may allow an unauthenticated attacker on the same subnet to intercept sensitive information by impersonating the Lightweight Directory Access Protocol (LDAP) server.

Sources

• CISA KEVConfirmed exploitationCVE-2019-5591

  Fortinet FortiOS contains a default configuration vulnerability that may allow an unauthenticated attacker on the same subnet to intercept sensitive information by impersonating the Lightweight Directory Access Protocol (LDAP) server.

  cisa.gov
• CVE.orgVulnerability recordCVE-2019-5591

  Official CVE identifier

  cve.org
• FIRST EPSSExploitation probabilityCVE-2019-5591

  30-day exploitation probability 18.6%

  first.org
• NIST NVDVulnerability recordCVE-2019-5591

  A Default Configuration vulnerability in FortiOS may allow an unauthenticated attacker on the same subnet to intercept sensitive information by impersonating the LDAP server.

  nvd.nist.gov
• VulnCheck KEVConfirmed exploitationCVE-2019-5591

  Fortinet FortiOS contains a default configuration vulnerability that may allow an unauthenticated attacker on the same subnet to intercept sensitive information by impersonating the Lightweight Directory Access Protocol (LDAP) server.

  vulncheck.com

References

• VulnCheck exploitation evidence · cisa.gov
• CISA note · nvd.nist.gov
• VulnCheck exploitation evidence · us-cert.cisa.gov
• US Government Resource · cisa.gov
• VulnCheck exploitation evidence · cisa.gov
• VulnCheck exploitation evidence · cisa.gov
• Mitigation · fortiguard.com
• VulnCheck exploitation evidence · ic3.gov
• VulnCheck exploitation evidence · ic3.gov

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.