---
id: CVE-2019-5591
title: >-
  A Default Configuration vulnerability in FortiOS may allow an unauthenticated
  attacker on the same subnet to intercept sensitive information by
  impersonating the LDAP server.
summary: >-
  A Default Configuration vulnerability in FortiOS may allow an unauthenticated
  attacker on the same subnet to intercept sensitive information by
  impersonating the LDAP server.
severity: medium
cvss: 6.5
cvssVector: 'CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N'
cwe:
  - CWE-306
  - CWE-306
vendor: fortinet
product: fortios
affected:
  - fortios <= 6.2.0
published: '2020-08-14'
updated: '2026-08-15'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2019-5591'
references:
  - url: 'https://www.fortiguard.com/psirt/FG-IR-19-037'
    label: psirt@fortinet.com
  - url: 'https://www.fortiguard.com/psirt/FG-IR-19-037'
    label: af854a3a-2127-422b-91ae-364da2661108
  - url: >-
      https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2019-5591
    label: 134c704f-9b21-4f2e-91b3-4a467353bcc0
tags:
  - nvd
  - kev
  - in-the-wild
  - exploit-available
epss: 0.18422
epssPercentile: 0.97107
kev: true
kevDateAdded: '2021-11-03'
kevDueDate: '2022-05-03'
kevRansomware: true
exploited: true
ingestedAt: '2026-08-15T04:24:40.604Z'
exploits:
  github: 1
  githubRepos:
    - 'https://github.com/ayewo/fortios-ldap-mitm-poc-CVE-2019-5591'
  nuclei:
    - CVE-2019-5591
  checkedAt: '2026-09-23T07:13:16.068Z'
exploitAvailable: true
---

## Overview

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

## Affected

- `fortios <= 6.2.0`

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.