6.5

CVE-2019-5591: Fortinet FortiOS Default Configuration Vulnerability

KEVRansomware
Analyzed
Published 14-08-2020Last modified 15-08-2026

Vulnerability summary

CVE-2019-5591 is a medium (CVSS 6.5) vulnerability in Fortinet FortiOS. It is known to be exploited: CISA lists it, first on 03-11-2021. It has been used in ransomware campaigns. EPSS estimates a 18.57% chance of exploitation in the next 30 days, higher than 97.2% of scored vulnerabilities.

Overall risk
90/100
0100
Critical · default modelHow is this calculated?
CVSS score
6.5/10
010
Medium · v3.1 (CVE.org)
EPSS score
18.57%
0%100%
Medium · +0.14 pp in 30 days
KEVExploited in the wildCritical · listed in 1 catalog
RansomwareKnown useFlagged by CISA
Public exploits0No public exploits recorded

Timeline

  1. 14-08-2020
    PublishedVulnerability first disclosed.
  2. 03-11-2021
    Added to CISA KEVExploitedFortinet FortiOS Default Configuration Vulnerability
  3. 03-05-2022
    CISA remediation dueDeadline passedApply updates per vendor instructions.
  4. 15-08-2026
    Last modifiedVulnerability information updated.

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.

CVSS metrics

3 scores · 2 sources · 2 versions

EPSS trend

Probability

18.57%

Chance of exploitation in the next 30 days

Percentile

97%

Versus all other CVEs

30-day change

Increase +0.14 pp

From 18.42% on 22-09-2026

22-09-202622-10-2026

Known exploited

Compare KEV catalogs
CISA KEVListed
Added
03-11-2021
Federal due date
03-05-2022
Ransomware
ENISA CNW

Not in the ENISA CNW catalog.

CIRCL

Not in the CIRCL catalog.

CISA required action

Apply updates per vendor instructions. nvd.nist.gov/vuln/detail/CVE-2019-5591

Public exploits

0 found

No public exploits indexed.

Weaknesses

CWE · root cause

Affected systems

Fortinet2 products

1 vendor · 2 products

References

2 links