What’s Vulnerable › Vulnerabilities

CVE-2021-43206

• Severity: medium (CVSS 4.3 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.8% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2022-05-04 · updated 2026-06-17
• Weakness: CWE-209

Description

A server-generated error message containing sensitive information in Fortinet FortiOS 7.0.0 through 7.0.3, 6.4.0 through 6.4.8, 6.2.x, 6.0.x and FortiProxy 7.0.0 through 7.0.1, 2.0.x allows malicious webservers to retrieve a web proxy's client username and IP via same origin HTTP requests triggering proxy-generated HTTP status codes pages.

Affected products

• Fortinet FortiOS (FortiGate): from 5.6.0 before 6.0.14; from 6.2.0 before 6.2.10; from 6.4.0 before 6.4.8; from 7.0.0 before 7.0.4 — fixed in 6.0.14, 6.2.10, 6.4.8, 7.0.4
• Fortinet FortiProxy: from 2.0.0 before 2.0.9; from 7.0.0 before 7.0.2 — fixed in 2.0.9, 7.0.2

How to fix

Upgrade to a fixed version: Fortinet FortiOS (FortiGate) 6.0.14, 6.2.10, 6.4.8, 7.0.4; Fortinet FortiProxy 2.0.9, 7.0.2. Check the vendor advisory for mitigations.

References

• https://fortiguard.com/psirt/FG-IR-21-231
• https://fortiguard.com/psirt/FG-IR-21-231

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