CVE-2022-23439: 
FortiOS vulnerability analysis and mitigation

A vulnerability identified as CVE-2022-23439 was discovered in multiple Fortinet products, classified as an externally controlled reference to a resource in another sphere vulnerability [CWE-610]. The vulnerability affects various Fortinet products including FortiOS, FortiProxy, FortiMail, FortiSwitch, FortiVoice, FortiNDR, FortiWLC, FortiADC, FortiAuthenticator, and several others across multiple versions (Fortiguard PSIRT, CVE Mitre).

The vulnerability allows an unauthenticated attacker to poison web caches between the device and the attacker through crafted HTTP requests, where the Host header points to an arbitrary webserver. The vulnerability has been assigned a CVSS v3 score of 4.1, indicating medium severity (Fortiguard PSIRT).

If successfully exploited, this vulnerability could lead to improper access control, potentially allowing attackers to manipulate web cache content between the device and users (Fortiguard PSIRT).

Fortinet has released multiple security updates to address this vulnerability. Users are advised to upgrade to the latest versions of affected products. For FortiOS, upgrades to version 7.0.6 and above or 7.2.1 and above are recommended. Additionally, specific configuration changes are required, such as setting the admin-host property to the device hostname to disable Host redirection. Similar upgrade paths and configuration changes are recommended for other affected products (Fortiguard PSIRT).

The vulnerability was internally reported and discovered by Théo Leleu of the Fortinet Product Security team (Fortiguard PSIRT).