What is CVE-2019-5591?

CVE-2019-5591 is a medium-severity vulnerability in Fortinet Fortios, classified under Missing Authentication for Critical Function. CVSS score: 6.5/10. Published 2020-08-14.

How severe is CVE-2019-5591?

Medium severity. CVSS v3 base score is 6.5 out of 10.

Is CVE-2019-5591 known to be exploited?

Yes. CVE-2019-5591 is listed in the CISA Known Exploited Vulnerabilities catalog (added 2021-11-03), indicating it is being actively exploited. 8 public proof-of-concept repositories are indexed.

Auth bypass in Fortinet Fortios

CVE-2019-5591

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

Vulnerability class: Broken Authentication

EPSS: 0.186 (96.9th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 6.5 (Medium). Vector: CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N.

Affected products

Fortinet Fortios — versions FortiOS 6.2.0 and below.
Fortinet Fortios

Weakness classification (CWE)

CWE-306 — Missing Authentication for Critical Function

CISA KEV (Known Exploited Vulnerabilities)

This CVE is on the CISA KEV catalog, added on 2021-11-03. CISA KEV inclusion means CISA has confirmed in-the-wild exploitation; US federal agencies are required to remediate within a published due date.

BOD 22-01 due date: 2022-05-03.

Required action: Apply updates per vendor instructions.

Public proof-of-concept exploits

References

psirt@fortinet.com (x_refsource_CONFIRM, Mitigation, Vendor Advisory)
134c704f-9b21-4f2e-91b3-4a467353bcc0 (US Government Resource)

Frequently asked questions

What is CVE-2019-5591?: CVE-2019-5591 is a medium-severity vulnerability in Fortinet Fortios, classified under Missing Authentication for Critical Function. CVSS score: 6.5/10. Published 2020-08-14.
How severe is CVE-2019-5591?: Medium severity. CVSS v3 base score is 6.5 out of 10.
Is CVE-2019-5591 known to be exploited?: Yes. CVE-2019-5591 is listed in the CISA Known Exploited Vulnerabilities catalog (added 2021-11-03), indicating it is being actively exploited. 8 public proof-of-concept repositories are indexed.