CVE-2026-59839

A vulnerability in Fortinet FortiOS allows a remote unauthenticated attacker to bypass the patch developed for the symbolic link persistency mechanism observed in some post-exploit cases. The attack requires prior compromise of the product via another vulnerability at the filesystem level.

An authentication bypass vulnerability in FortiOS and FortiProxy allows a remote unauthenticated attacker, with prior knowledge of upstream and downstream device serial numbers, to gain super-admin privileges on the downstream device if Security Fabric is enabled. The attack is carried out via crafted CSF proxy requests.

An authentication bypass vulnerability in FortiOS and FortiProxy using an alternate path or channel. A remote attacker can gain super-admin privileges by sending crafted requests to the Node.js websocket module.

An authentication bypass vulnerability in FortiOS, FortiProxy, and FortiSwitchManager allows an unauthenticated attacker to perform operations on the administrative interface via crafted HTTP or HTTPS requests.

A Default Configuration vulnerability in FortiOS may allow an unauthenticated attacker on the same subnet to intercept sensitive information by impersonating the LDAP server.

An improper authentication vulnerability in SSL VPN in FortiOS 6.4.0, 6.2.0 to 6.2.3, 6.0.9 and below may result in a user being able to log in successfully without being prompted for the second factor of authentication (FortiToken) if they changed the case of their username.

Use of a hard-coded cryptographic key to cipher sensitive data in FortiOS configuration backup file may allow an attacker with access to the backup file to decipher the sensitive data, via knowledge of the hard-coded key. The aforementioned sensitive data includes users' passwords (except the administrator's password), private keys' passphrases and High Availability password (when set).