CVE-2019-5591

lowpriority · act · 90OT risk · criticalKEV · exploitedEPSS 0.186 · 97 %ileexploit · PoCEURUUS

grimoire priorityP0 · Act now

Exploitable?

Yes · in the wild

CISA KEV · 1 exploit · PoC

Likely / severe?

18.6% (97th) EPSS

CVSS 3.3 · low

Is it mine?

3 products

Check your exposure

Who says so?

4 sources

cnnvd · enisa_euvd · fstec_bdu · nvd

added 2021-11-03remediate by 2022-05-03

required action Apply updates per vendor instructions.

EPSS · scored 2026-10-22

Fortinet FortiOS Default Configuration Vulnerability

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

Technical severity, 0–10. One row per scoring source.

6.5

010

base score 0–10 · higher = more severe · hover a vector to decode⚠ sources disagree · low–medium · 3.1–6.5

v2.03.3lowAV:A/AC:L/Au:N/C:P/I:N/A:Nprimary · NVD / NIST USexploitability 6.5 · impact 2.9

v3.16.5mediumCVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:Nprimary · NVD / NIST USexploitability 2.8 · impact 3.6

v3.13.1lowAV:A/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:Nsecondary · FSTEC (BDU) RU

v3.16.5mediumCVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:Nsecondary · ENISA EU

v3.16.5mediumCVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:Nsecondaryexploitability 2.8 · impact 3.6

v3.16.5mediumCVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N/E:Hsecondary · CVSS-BT (t0sche)

ssvc

A stakeholder decision — act, attend, or track — from exploitation and impact.

Exploitation: active · Automatable: no · Technical Impact: partialcoordinatorcisa_ssvcUS

weaknesses

The CWE weakness classes this flaw belongs to.

CWE-306USprimaryCWE-285USCWE-345US

ATT&CK techniques

ATT&CK techniques this enables or maps to.

exploits (1)

Public proof-of-concept and weaponised exploit code.

ayewo/fortios-ldap-mitm-poc-CVE-2019-5591The 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. PoC · poc_in_github

affected products (3)

Products and version ranges known to be affected.

Fortinet Fortinet FortiOS≤ FortiOS 6.2.0 and below.enisa_euvdEU
Fortinet Inc. FortiOS≤ 6.2.0fstec_bduRU
fortinet fortios≤ 6.2.0nvdUScpe:2.3:o:fortinet:fortios:*:*:*:*:*:*:*:*

also known as (5)

Other names and identifiers for this entity.

sources

Which sources assert this record, and when.

cnnvd enisa_euvd fstec_bdu nvd NVD CVE.org MITRE

published 2020-08-14modified 2026-08-15

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references (9)

External citations — patches, advisories, analysis.

scry

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