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.
Key facts
- CVSS score
- 6.5 (v3.1)
- Severity
- MEDIUM
- CVSS vector
CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N- Weakness (CWE)
- CWE-306
- EPSS score
- 18.6% (97th percentile)
- In CISA KEV
- Yes, added November 3, 2021
- In EU EUVD
- Yes (EUVD-2019-15166)
- Published
- August 14, 2020
- NVD last modified
- August 15, 2026
- Status
- Analyzed
CISA Known Exploited Vulnerability
Fortinet FortiOS Default Configuration Vulnerability
Added to the KEV catalog on November 3, 2021; federal remediation due May 3, 2022. Known to be used in ransomware campaigns.
EU Vulnerability Database (EUVD)
This vulnerability is also tracked by ENISA as EUVD-2019-15166 in the EU Vulnerability Database. ENISA flags it as known exploited. Last updated in EUVD on August 15, 2026.
View on the EU Vulnerability DatabaseAffected products
- fortinet / fortios
Certified products that may be affected
4 FIPS 140 or Common Criteria certified products, from automated matching by sec-certs.org.
- FortiOS 5.6 - Fortinet, Inc. - FIPS 140 3639 - historical
- FortiOS 5.2 - Fortinet, Inc. - FIPS 140 2765 - historical
- FortiOS™ - Fortinet, Inc. - FIPS 140 1754 - historical
- FortiOS - Fortinet, Inc. - FIPS 140 1431 - historical
References
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2019-5591(US Government Resource)
- https://www.fortiguard.com/psirt/FG-IR-19-037(Mitigation, Vendor Advisory)
Last updated September 17, 2026 · Source: NVD, CISA KEV, FIRST.org EPSS
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