Vulnerability DatabaseCVE-2023-42786

CVE-2023-42786:
FortiOS vulnerability analysis and mitigation

Overview

A null pointer dereference vulnerability (CVE-2023-42786) was identified in FortiOS's SSL-VPN component. The vulnerability was initially published on January 14, 2025, affecting multiple versions of FortiOS including versions 7.4.0 through 7.4.1, 7.2.0 through 7.2.5, and all versions of 7.0, 6.4, 6.2, and 6.0. This vulnerability has been assigned a medium severity rating with a CVSSv3 score of 6.4 (Fortiguard PSIRT).

Technical details

The vulnerability is classified as a null pointer dereference [CWE-476] in FortiOS that can be triggered through the SSL-VPN component. The issue allows a remote attacker with low privileges to crash the VPN service by sending a crafted HTTP request (Fortiguard PSIRT).

Impact

The successful exploitation of this vulnerability results in a Denial of Service (DoS) condition, specifically causing the VPN service to crash. This can lead to service disruption for legitimate users attempting to access resources through the SSL-VPN (Fortiguard PSIRT).

Mitigation and workarounds

Fortinet has released patches to address this vulnerability. Users of FortiOS 7.4.0-7.4.1 should upgrade to version 7.4.2 or above, while users of FortiOS 7.2.0-7.2.5 should upgrade to version 7.2.6 or above. Users of FortiOS 7.0, 6.4, 6.2, and 6.0 (all versions) should migrate to a fixed release. Additionally, Fortinet has remediated this issue in FortiSASE version 23.4 (Fortiguard PSIRT).

Community reactions

The vulnerability was discovered and reported by security researcher Qian Chen (@cq674350529) from Codesafe Team of Legendsec at QI-ANXIN Group under responsible disclosure practices (Fortiguard PSIRT).