CVE-2025-47890 is an open redirect vulnerability identified in Fortinet FortiSASE version 25.2.a, as well as multiple versions of FortiOS (6.4 through 7.6.3) and FortiProxy products. The vulnerability stems from improper access control that allows unauthenticated attackers to craft malicious HTTP requests that cause the affected system to redirect users to untrusted external websites. This type of vulnerability is categorized under CWE-601 (URL Redirection to Untrusted Site). The attack vector is network-based (AV:A), requires high attack complexity (AC:H), no privileges (PR:N), but does require user interaction (UI:R). The scope is unchanged (S:U), and the impact on confidentiality is none (C:N), integrity is low (I:L), and availability is none (A:N). The CVSS score is 2.5, reflecting a low severity. The vulnerability does not allow direct compromise of the system but can be leveraged for social engineering, phishing, or redirecting users to malicious sites. No known exploits have been reported in the wild as of the publication date (October 14, 2025). The vulnerability affects a broad range of Fortinet products widely used for network security and secure access service edge (SASE) deployments. The root cause is insufficient validation of redirect URLs, enabling attackers to manipulate redirection targets.

For European organizations, the primary impact of CVE-2025-47890 is the increased risk of phishing and social engineering attacks facilitated by malicious redirects. While the vulnerability itself does not allow direct system compromise or data breach, it can be exploited to redirect users to malicious websites that may attempt credential theft, malware delivery, or other fraud. Organizations relying on Fortinet FortiSASE and related FortiOS/FortiProxy products for secure remote access and network security could see increased exposure if attackers leverage this flaw in targeted campaigns. The impact is particularly relevant for sectors with high security requirements such as finance, government, and critical infrastructure. However, the low CVSS score and requirement for user interaction limit the overall risk. Still, successful exploitation could undermine user trust and lead to secondary attacks. The absence of known exploits in the wild suggests limited immediate threat but does not preclude future exploitation.

To mitigate CVE-2025-47890, organizations should implement the following specific measures: 1) Apply vendor patches or updates as soon as they become available to FortiSASE, FortiOS, and FortiProxy products. 2) Configure strict URL validation and whitelisting policies within Fortinet products to restrict allowable redirect targets. 3) Employ web filtering and DNS filtering solutions to block access to known malicious domains and suspicious redirect URLs. 4) Enhance user awareness training focusing on recognizing suspicious links and phishing attempts, emphasizing caution with unexpected redirects. 5) Monitor network traffic and logs for unusual redirect patterns or HTTP requests indicative of exploitation attempts. 6) Consider deploying multi-factor authentication (MFA) to reduce the impact of credential theft resulting from phishing. 7) Coordinate with Fortinet support to confirm if any interim workarounds or configuration changes can reduce exposure prior to patching. These steps go beyond generic advice by focusing on Fortinet-specific configurations and user behavior controls.