# CVE-2019-5591: Fortinet FortiOS Default Configuration Vulnerability

Source: https://junglewise.ai/threats/cve-2019-5591-fortinet-fortios-default-configuration-vulnerability  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2021-11-03. Updated: 2026-05-10  
License: CC BY 4.0 with a link back

CVE-2019-5591 · Severity: critical · CVSS 6.5 · Exploited in the wild · Published 2021-11-03

A default configuration vulnerability in Fortinet FortiOS allows an unauthenticated attacker on the same subnet to intercept sensitive information. This is achieved by impersonating the LDAP server due to missing authentication for critical functions.

Technologies: [Fortinet FortiOS](https://junglewise.ai/threats/technologies/fortios). Vendors: [Fortinet](https://junglewise.ai/threats/vendors/fortinet).

## Quick answers

**Is CVE-2019-5591 exploited in the wild?** Yes. CVE-2019-5591 is known to be exploited in the wild, first recorded on 3 November 2021. Treat it as urgent.

**How severe is CVE-2019-5591?** Critical severity, with a CVSS score of 6.5, published 3 November 2021.

**Which products and versions are affected?** Fortinet FortiOS up to and including 6.2.0.

**Is there a fix for CVE-2019-5591?** No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.

**How is CVE-2019-5591 attacked?** It is attacked from the adjacent network, in an operating system.

**Am I affected by CVE-2019-5591?** Check whether you run Fortinet FortiOS. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## Affected products

- Fortinet FortiOS up to and including 6.2.0

## Timeline

- 2020-08-14: disclosed: NVD Published Date
- 2021-11-03: kev added: Date added to CISA Known Exploited Vulnerabilities Catalog
- 2021-11-03: advisory: CISA advisory publication date

## Related threats

- [Fortinet FortiOS authentication bypass in HA command execution](https://junglewise.ai/threats/cve-2026-126259-a-missing-authentication-for-critical-function-vulnerability-in)
- [Fortinet FortiOS stack buffer overflow in WAD proxy](https://junglewise.ai/threats/cve-2026-126258-a-stack-based-buffer-overflow-vulnerability-in-fortinet-fortios)
- [Fortinet FortiOS out-of-bounds read in kernel](https://junglewise.ai/threats/cve-2026-126256-a-out-of-bounds-read-vulnerability-in-fortinet-fortios-8-0-0)
- [Fortinet FortiOS path traversal authentication bypass in SSH daemon](https://junglewise.ai/threats/cve-2026-126255-a-path-traversal-filedir-vulnerability-in-fortinet-fortios-8-0-0)
- [Fortinet FortiOS numeric truncation error in BGP daemon](https://junglewise.ai/threats/cve-2026-126254-a-numeric-truncation-error-vulnerability-in-fortinet-fortios-8-0)