CVE-2019-5591 Fortinet FortiOS: login or permission bypass
In plain words: A door that should be locked is not: part of the system can be reached without a valid login or permission. The attacker gets in as a user or administrator without knowing a password.
Confirmed exploited by CISA on · US federal patch deadline May 3, 2022
What to do
- Install Fortinet's security update for FortiOS. If no update exists, follow the vendor's workaround or stop using the product until one ships.
- Patch edge devices first — attackers often start scanning for them within hours of a fix.
- Never expose the device's admin page to the internet.
- After patching a device that was exposed, follow the vendor's compromise checks, end active sessions and change passwords.
Who is affected
Work IT. Aimed mostly at company systems — you are affected through the companies you use, not your own phone.
What's at risk: They face the internet and guard the whole network, so a flaw here can hand attackers a way in — and these devices usually run no antivirus, so break-ins go unnoticed.
The details
- Official name
- Fortinet FortiOS Default Configuration Vulnerability
- Product
- Fortinet FortiOS
- CISA description
- Fortinet FortiOS contains a default configuration vulnerability that may allow an unauthenticated attacker on the same subnet to intercept sensitive information by impersonating the Lightweight Directory Access Protocol (LDAP) server.
- Type of flaw
- Login or permission bypass (CWE-306)
- Confirmed exploited
- Nov 3, 2021 — known to be used in ransomware attacks
- US federal patch deadline
- May 3, 2022
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Answering about CVE-2019-5591 ·
Questions about CVE-2019-5591
Is CVE-2019-5591 being exploited?
Yes. CISA added CVE-2019-5591 to its Known Exploited Vulnerabilities catalog on Nov 3, 2021, which means there is reliable evidence of real-world attacks, including by ransomware groups.
How do I fix CVE-2019-5591?
Install Fortinet's security update for FortiOS. If no update exists, follow the vendor's workaround or stop using the product until one ships. Patch edge devices first — attackers often start scanning for them within hours of a fix.
Am I affected by CVE-2019-5591?
Only if you use Fortinet FortiOS. Aimed mostly at company systems — you are affected through the companies you use, not your own phone.