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Known Exploited Vulnerability
6.5
MEDIUM CVSS 3.1
CVE-2019-5591
Fortinet FortiOS Default Configuration Vulnerability - [Actively Exploited]
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.

INFO

Published Date :

Aug. 14, 2020, 4:15 p.m.

Last Modified :

Oct. 24, 2025, 12:54 p.m.

Remotely Exploit :

No

Source :

[email protected]
CISA Notification
CISA KEV (Known Exploited Vulnerabilities)

For the benefit of the cybersecurity community and network defenders—and to help every organization better manage vulnerabilities and keep pace with threat activity—CISA maintains the authoritative source of vulnerabilities that have been exploited in the wild.

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.

Required Action :

Apply updates per vendor instructions.

Notes :

https://nvd.nist.gov/vuln/detail/CVE-2019-5591

Affected Products

The following products are affected by CVE-2019-5591 vulnerability. Even if cvefeed.io is aware of the exact versions of the products that are affected, the information is not represented in the table below.

ID Vendor Product Action
1 Fortinet fortios
: Total Affected Vendor : 1 | Products : 1
CVSS Scores
The Common Vulnerability Scoring System is a standardized framework for assessing the severity of vulnerabilities in software and systems. We collect and displays CVSS scores from various sources for each CVE.
Score Version Severity Vector Exploitability Score Impact Score Source
CVSS 2.0 LOW [email protected]
CVSS 3.1 MEDIUM [email protected]
CVSS 3.1 MEDIUM 134c704f-9b21-4f2e-91b3-4a467353bcc0
Solution
This information is provided by the 3rd party feeds.
  • Upgrade to Fortinet FortiOS version 6.2.1 or later.
Public PoC/Exploit Available at Github

CVE-2019-5591 has a 5 public PoC/Exploit available at Github. Go to the Public Exploits tab to see the list.

References to Advisories, Solutions, and Tools

Here, you will find a curated list of external links that provide in-depth information, practical solutions, and valuable tools related to CVE-2019-5591.

URL Resource
https://www.fortiguard.com/psirt/FG-IR-19-037 Mitigation Vendor Advisory
https://www.fortiguard.com/psirt/FG-IR-19-037 Mitigation Vendor Advisory
https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2019-5591 US Government Resource
CWE - Common Weakness Enumeration

While CVE identifies specific instances of vulnerabilities, CWE categorizes the common flaws or weaknesses that can lead to vulnerabilities. CVE-2019-5591 is associated with the following CWEs:

Common Attack Pattern Enumeration and Classification (CAPEC)

Common Attack Pattern Enumeration and Classification (CAPEC) stores attack patterns, which are descriptions of the common attributes and approaches employed by adversaries to exploit the CVE-2019-5591 weaknesses.

We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).

Profile Photo
ayewo/fortios-ldap-mitm-poc-CVE-2019-5591

The default configuration of LDAP on FortiOS v6.0.x to v6.2.0 does not check server identity for LDAP/S leading to MITM attacks. This PoC demos full exfiltration of credentials sent on the local subnet to an LDAP server that is easily impersonated.

Python Dockerfile

Updated: 1 week, 6 days ago
0 stars 0 fork 0 watcher
Born at : Oct. 16, 2025, 10:18 p.m. This repo has been linked 1 different CVEs too.
Profile Photo
soosmile/POC

None

Updated: 6 months, 4 weeks ago
9 stars 1 fork 1 watcher
Born at : June 21, 2022, 7:45 a.m. This repo has been linked 944 different CVEs too.
Profile Photo
triw0lf/Security-Matters-22

Resources for Security Matters talk 2022

Updated: 3 years, 6 months ago
1 stars 0 fork 0 watcher
Born at : April 20, 2022, 5:31 p.m. This repo has been linked 39 different CVEs too.
Profile Photo
Ostorlab/KEV

Ostorlab KEV: One-command to detect most remotely known exploitable vulnerabilities. Sourced from CISA KEV, Google's Tsunami, Ostorlab's Asteroid and Bug Bounty programs.

cisa-kev vulnerability 0day cisa exploits

Updated: 2 weeks, 6 days ago
588 stars 42 fork 42 watcher
Born at : April 19, 2022, 8:58 a.m. This repo has been linked 1290 different CVEs too.
Profile Photo
r0eXpeR/supplier

主流供应商的一些攻击性漏洞汇总

Updated: 3 months, 1 week ago
808 stars 143 fork 143 watcher
Born at : Nov. 8, 2021, 2:12 a.m. This repo has been linked 93 different CVEs too.

Results are limited to the first 15 repositories due to potential performance issues.

The following list is the news that have been mention CVE-2019-5591 vulnerability anywhere in the article.

Results are limited to the first 20 news articles due to potential performance issues.

The following table lists the changes that have been made to the CVE-2019-5591 vulnerability over time.

Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.

  • Modified Analysis by [email protected]

    Oct. 24, 2025

    Action Type Old Value New Value
    Added Reference Type CISA-ADP: https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2019-5591 Types: US Government Resource
  • CVE Modified by 134c704f-9b21-4f2e-91b3-4a467353bcc0

    Oct. 22, 2025

    Action Type Old Value New Value
    Added Reference https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2019-5591
  • CVE Modified by 134c704f-9b21-4f2e-91b3-4a467353bcc0

    Oct. 21, 2025

    Action Type Old Value New Value
    Removed Reference https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2019-5591
  • CVE Modified by 134c704f-9b21-4f2e-91b3-4a467353bcc0

    Oct. 21, 2025

    Action Type Old Value New Value
    Added Reference https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2019-5591
  • Modified Analysis by [email protected]

    Feb. 06, 2025

    Action Type Old Value New Value
  • CVE Modified by af854a3a-2127-422b-91ae-364da2661108

    Nov. 21, 2024

    Action Type Old Value New Value
    Added Reference https://www.fortiguard.com/psirt/FG-IR-19-037
  • Modified Analysis by [email protected]

    Oct. 24, 2024

    Action Type Old Value New Value
    Changed Reference Type https://www.fortiguard.com/psirt/FG-IR-19-037 Vendor Advisory https://www.fortiguard.com/psirt/FG-IR-19-037 Mitigation, Vendor Advisory
  • CVE Modified by 134c704f-9b21-4f2e-91b3-4a467353bcc0

    Oct. 23, 2024

    Action Type Old Value New Value
    Added CWE CISA-ADP CWE-306
    Added CVSS V3.1 CISA-ADP AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
  • CVE Modified by [email protected]

    May. 14, 2024

    Action Type Old Value New Value
  • CWE Remap by [email protected]

    Jul. 21, 2021

    Action Type Old Value New Value
    Changed CWE CWE-200 CWE-306
  • Modified Analysis by [email protected]

    Apr. 12, 2021

    Action Type Old Value New Value
    Removed CVSS V2 NIST (AV:N/AC:L/Au:N/C:P/I:N/A:N)
    Added CVSS V2 NIST (AV:A/AC:L/Au:N/C:P/I:N/A:N)
    Removed CVSS V3.1 NIST AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
    Added CVSS V3.1 NIST AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
    Changed Reference Type https://www.fortiguard.com/psirt/FG-IR-19-037 No Types Assigned https://www.fortiguard.com/psirt/FG-IR-19-037 Vendor Advisory
  • CVE Modified by [email protected]

    Apr. 07, 2021

    Action Type Old Value New Value
    Removed Reference https://fortiguard.com/advisory/FG-IR-19-037 [Vendor Advisory]
    Added Reference https://www.fortiguard.com/psirt/FG-IR-19-037 [No Types Assigned]
  • Initial Analysis by [email protected]

    Aug. 20, 2020

    Action Type Old Value New Value
    Added CVSS V2 NIST (AV:N/AC:L/Au:N/C:P/I:N/A:N)
    Added CVSS V3.1 NIST AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
    Changed Reference Type https://fortiguard.com/advisory/FG-IR-19-037 No Types Assigned https://fortiguard.com/advisory/FG-IR-19-037 Vendor Advisory
    Added CWE NIST CWE-200
    Added CPE Configuration OR *cpe:2.3:o:fortinet:fortios:*:*:*:*:*:*:*:* versions up to (including) 6.2.0
EPSS is a daily estimate of the probability of exploitation activity being observed over the next 30 days. Following chart shows the EPSS score history of the vulnerability.
Vulnerability Scoring Details
Base CVSS Score: 6.5
Attack Vector
Attack Complexity
Privileges Required
User Interaction
Scope
Confidentiality Impact
Integrity Impact
Availability Impact
Base CVSS Score: 3.3
Access Vector
Access Complexity
Authentication
Confidentiality Impact
Integrity Impact
Availability Impact
Exploit Prediction

EPSS is a daily estimate of the probability of exploitation activity being observed over the next 30 days.

3.62 }} 1.05%

score

0.87240

percentile