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CVE-2019-5591

6.5, medium Known exploited Used in ransomware

Fortinet FortiOS Default Configuration Vulnerability

NVD (opens in a new tab) CVE.org (opens in a new tab) CISA KEV catalogue (opens in a new tab)
CVSS
6.5, medium medium CVSS v3.1
EPSS, next 30 days
19% higher than 97.2% of scored CVEs
Exploitation
Confirmed in the wild
Published
14 Aug 20206 years ago

Known exploited

CISA added this to the Known Exploited Vulnerabilities Catalog on 3 Nov 2021 and links it to ransomware activity. US federal agencies had to remediate by 3 May 2022, a deadline that has passed.

Required action. Apply updates per vendor instructions.

Description

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

Details

Vendor
Fortinet
Product
Fortinet FortiOS
Weakness
CWE-306 (opens in a new tab)
Status
Analyzed
Updated
15 Aug 2026
Assigner
psirt@fortinet.com

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

References 2

Advisories 1

Other references 1

The kind is read from NVD's tags where present and from the shape of the URL otherwise, so treat it as a hint.

Other Fortinet CVEs

Every Fortinet CVE we hold

Same vendor in what we hold, not a known link between the flaws.

  • CVE-2026-104286 Fortinet FortiMail Path Traversal Vulnerability KEV EPSS 2% 9.8, critical
  • CVE-2026-25089 Fortinet FortiSandbox OS Command Injection Vulnerability KEV EPSS 76% 9.8, critical
  • CVE-2026-39808 Fortinet FortiSandbox OS Command Injection Vulnerability KEV EPSS 47% 9.8, critical
  • CVE-2025-61624 Fortinet Multiple Products Path Traversal Vulnerability KEV EPSS 0.6% 6.5, medium
  • CVE-2026-35616 Fortinet FortiClient EMS Improper Access Control Vulnerability KEV EPSS 9% 9.8, critical
  • CVE-2025-68686 Fortinet FortiOS Exposure of Sensitive Information to an Unauthorized Actor Vulnerability KEV EPSS 29% 5.9, medium
  • CVE-2026-21643 Fortinet FortiClient EMS SQL Injection Vulnerability KEV EPSS 94% 9.8, critical
  • CVE-2026-24858 Fortinet Multiple Products Authentication Bypass Using an Alternate Path or Channel Vulnerability KEV EPSS 86% 9.8, critical

Beyond this page

Is CVE-2019-5591 in your network?

This page tells you how dangerous CVE-2019-5591 is out there. Whether it sits on one of your devices, only a scan of your own network can tell. That is what our systems do, every day, for the companies we protect.

CVE-2019-5591 is in the CISA catalogue of exploited vulnerabilities: attackers are already exploiting it.

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  • EXYS7950 KONDRA

    Detect it if it's exploited

    Until the patch is applied, Kondra monitors your network, events and endpoints in real time. It keeps an inventory of the software installed on every endpoint, and its anomaly detection rules flag what an attacker does once inside.

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Check your exposure

Assembled from the NVD 2.0 API, the CISA Known Exploited Vulnerabilities Catalog and FIRST EPSS. Scores are as of our last collection on 17 Oct 2026, not the live upstream state.