CVE-2019-5591
KEVRansomware UseFortinet FortiOS Default Configuration Vulnerability
Description
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.
A Default Configuration vulnerability in FortiOS may allow an unauthenticated attacker on the same subnet to intercept sensitive information by impersonating the LDAP server.
CVSS 3.1 vector
CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:NPublishedAug 14, 2020
Last modifiedAug 15, 2026
Added to KEVNov 3, 2021
Remediation dueMay 3, 2022
References
- fortiguard.com/psirt/FG-IR-19-037MitigationVendor Advisory
- cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2019-5591US Government Resource
0 recent articles mention this CVE
74
Risk assessment · High
Actively exploited and used by ransomware crews. Patch immediately.
- Exploitation
- Confirmed in the wild (CISA KEV)
- Federal remediation deadline
- Overdue by 1637 days
- Ransomware
- Used in known ransomware campaigns
- CVSS
- 6.5 MEDIUM
- EPSS (30-day exploit probability)
- 18.6% · top 3% of all CVEs
- Weakness
- CWE-306
- Preconditions
- No privileges and no user interaction
Recommended actions
- 1.Apply updates per vendor instructions.
- 2.Treat as emergency change: patch or isolate internet-facing instances first.
- 3.Hunt for compromise: review logs for the disclosure window, not just from the patch date.
- 4.Verify offline/immutable backups and segment the affected systems. This flaw is used for ransomware initial access.
Assessment is derived automatically from the live signals above; verify against your own asset inventory.