CVE-2025-25248 is an Integer Overflow or Wraparound vulnerability affecting multiple versions of Fortinet's FortiOS, FortiProxy, and FortiPAM products. Specifically, it impacts FortiOS versions 6.4.x through 7.6.2, FortiProxy versions 2.0 through 7.6.2, and FortiPAM versions 1.0 through 1.5.0. The vulnerability resides in the handling of SSL-VPN Remote Desktop Protocol (RDP) and Virtual Network Computing (VNC) bookmarks. An authenticated user can send specially crafted requests that exploit the integer overflow condition, leading to a denial of service (DoS) condition that affects the availability of the SSL-VPN service on the device. The integer overflow likely occurs during processing of bookmark data structures, causing memory corruption or resource exhaustion that crashes or otherwise disrupts the SSL-VPN subsystem. The vulnerability requires low privileges (authenticated user) but no user interaction beyond sending crafted requests. The CVSS v3.1 base score is 4.8 (medium severity), reflecting the network attack vector, the requirement for low privileges, and the impact limited to availability without confidentiality or integrity compromise. There are no known exploits in the wild at the time of publication, and no patches or mitigations have been explicitly linked in the provided data. This vulnerability could be leveraged by an insider or compromised user account to disrupt remote access services, potentially impacting business continuity and incident response capabilities.

For European organizations, this vulnerability poses a risk primarily to the availability of remote access infrastructure. Fortinet FortiOS and related products are widely deployed in enterprise and service provider environments across Europe for VPN and network security functions. A successful exploitation could disrupt SSL-VPN services, denying legitimate users remote access to corporate networks. This can hinder business operations, especially for organizations relying heavily on remote work or third-party access. Critical sectors such as finance, healthcare, government, and telecommunications could experience operational interruptions. While the vulnerability does not directly expose confidential data or allow integrity breaches, the denial of service could indirectly affect incident response, system maintenance, and continuity of operations. The requirement for authenticated access limits the attack surface to insiders or compromised accounts, but given the prevalence of phishing and credential theft, this remains a realistic threat vector. The absence of known exploits suggests limited immediate risk, but the medium severity rating and broad affected versions warrant prompt attention.

European organizations should prioritize the following mitigations: 1) Immediate inventory and identification of Fortinet FortiOS, FortiProxy, and FortiPAM devices within their environment, including version verification to determine exposure. 2) Apply vendor-released patches or firmware updates as soon as they become available; monitor Fortinet advisories closely. 3) Restrict SSL-VPN access to trusted users and enforce strong authentication mechanisms such as multi-factor authentication (MFA) to reduce the risk of credential compromise. 4) Implement network segmentation and access controls to limit the ability of authenticated users to send crafted requests to vulnerable devices. 5) Monitor SSL-VPN logs and network traffic for anomalous patterns indicative of exploitation attempts, such as unusual bookmark modification requests or repeated connection resets. 6) Conduct regular vulnerability scanning and penetration testing focused on VPN infrastructure to detect potential weaknesses. 7) Educate users on phishing and credential security to reduce the risk of account compromise. 8) Prepare incident response plans that include procedures for rapid isolation and recovery of affected VPN devices to minimize downtime.