CVE-2025-31514 is a vulnerability classified as CWE-532 (Insertion of Sensitive Information into Log File) affecting Fortinet FortiProxy products running FortiOS versions 6.4.x, 7.0.x, 7.2.x, 7.4.x, and 7.6.0 through 7.6.3. The flaw allows an attacker who has at least read-only privileges on the FortiProxy device to retrieve sensitive information related to two-factor authentication (2FA) by inspecting log files or executing diagnostic commands. This vulnerability stems from improper handling of sensitive data, which is inadvertently logged in plaintext or accessible logs, thereby exposing 2FA secrets or tokens. The attacker does not require user interaction but does need some level of authenticated access, which limits the attack surface to insiders or users with limited privileges. The CVSS v3.1 score is 2.6, reflecting low severity due to the requirement of privileges and the limited scope of impact (confidentiality only, no integrity or availability impact). No public exploits or widespread attacks have been reported to date. Fortinet has not yet published patches or mitigation details, but the issue is recognized and documented. This vulnerability could facilitate further attacks if combined with credential compromise or privilege escalation, as exposure of 2FA information weakens multi-factor authentication protections.

For European organizations, the primary impact is the potential compromise of 2FA secrets, which undermines the security of authentication processes protecting critical systems. This could lead to unauthorized access if attackers leverage the disclosed information alongside other credentials. While the vulnerability requires read-only access, insider threats or compromised low-privilege accounts could exploit this to escalate attacks. Organizations relying on FortiProxy for secure web gateway or proxy services, especially in sectors like finance, government, and critical infrastructure, may face increased risk of credential theft and subsequent breaches. The confidentiality breach could erode trust in multi-factor authentication deployments and complicate incident response. However, since the vulnerability does not affect system integrity or availability, direct service disruption is unlikely. The absence of known exploits reduces immediate risk but does not eliminate the need for vigilance.

To mitigate this vulnerability, European organizations should immediately audit and restrict read-only access to FortiProxy logs and diagnostic commands, ensuring only trusted administrators have such privileges. Implement strict role-based access controls (RBAC) and monitor access logs for unusual activity. Until patches are available, consider disabling or limiting diagnostic commands that expose sensitive 2FA information. Regularly review and sanitize logs to remove sensitive data where feasible. Employ network segmentation to isolate FortiProxy management interfaces from general user access. Enhance monitoring for insider threats and anomalous access patterns. When Fortinet releases patches or updates addressing this issue, prioritize their deployment in all affected environments. Additionally, reinforce multi-factor authentication mechanisms by using hardware tokens or out-of-band verification methods less susceptible to information leakage.