CVE-2025-57740: 
FortiOS vulnerability analysis and mitigation

A Heap-based Buffer Overflow vulnerability (CVE-2025-57740) was discovered in FortiOS, FortiPAM, and FortiProxy RDP bookmark connection functionality. The vulnerability was disclosed on October 14, 2025, affecting multiple versions of FortiOS (6.4-7.6), FortiPAM (1.0-1.5), and FortiProxy (7.0-7.6). This medium severity vulnerability, with a CVSSv3 score of 6.7, was identified by security researchers Vang3lis and Cyth from VARAS@IIE (Fortinet Advisory, NVD).

The vulnerability is classified as a Heap-based Buffer Overflow (CWE-122) that exists in the SSL-VPN bookmarks feature, specifically affecting the RDP bookmark connection functionality. The vulnerability requires authentication for exploitation and has been assigned a CVSS v3.1 Base Score of 8.8 HIGH (NIST:NVD) with vector string CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H, though Fortinet's assessment rates it at 7.5 HIGH with vector string CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H (NVD).

When successfully exploited, this vulnerability allows an authenticated user to execute unauthorized code via crafted requests. The potential impact includes high severity compromises of system confidentiality, integrity, and availability, as indicated by the CVSS metrics (Fortinet Advisory).

Fortinet has released patches for affected versions and recommends upgrading to the following versions: FortiOS 7.6.3 or above (for 7.6.x), 7.4.8 or above (for 7.4.x), 7.2.11 or above (for 7.2.x); FortiPAM 1.5.1 or above (for 1.5.x), 1.4.3 or above (for 1.4.x); FortiProxy 7.6.3 or above (for 7.6.x), 7.4.4 or above (for 7.4.x). Users on older versions are advised to migrate to a fixed release. Fortinet provides an upgrade path tool at their documentation site (Fortinet Advisory).