CVE-2025-25248: 
FortiOS vulnerability analysis and mitigation

An Integer Overflow or Wraparound vulnerability (CVE-2025-25248) was discovered in FortiOS, FortiPAM, and FortiProxy SSL-VPN RDP and VNC bookmarks functionality. The vulnerability was initially disclosed on August 12, 2025, affecting multiple versions of FortiOS (versions 7.6.2 and below, 7.4.7 and below, 7.2.10 and below, all versions of 7.2 and 6.4), FortiProxy (versions 7.6.2 and below, 7.4.3 and below, all versions of 7.2, 7.0, and 2.0), and FortiPAM (version 1.5.0, version 1.4.2 and below, all versions of 1.3, 1.2, 1.1, and 1.0) (Fortinet Advisory).

The vulnerability is classified as CWE-190 (Integer Overflow or Wraparound) and received a CVSS v3.1 base score of 6.5 (Medium) from NVD and 5.3 (Medium) from Fortinet. The issue specifically affects the SSL-VPN RDP and VNC bookmarks functionality in the affected products, where integer overflow conditions can be triggered through crafted requests (NVD).

When successfully exploited, this vulnerability can affect the device SSL-VPN availability, potentially leading to denial of service conditions. The impact is limited to authenticated users who have access to the SSL-VPN functionality (Fortinet Advisory).

Fortinet has released patches for affected versions and recommends upgrading to the following versions: FortiOS - upgrade to 7.6.3, 7.4.8, or 7.2.11; FortiPAM - upgrade to 1.5.1 or 1.4.3; FortiProxy - upgrade to 7.6.3 or 7.4.4. For older versions that cannot be upgraded, users are advised to migrate to a fixed release. Fortinet provides an upgrade path tool to assist with the update process (Fortinet Advisory).

The vulnerability was responsibly disclosed by security researchers Vang3lis and TangentHuang from VARAS@IIE, demonstrating effective collaboration between security researchers and vendors (Fortinet Advisory).