CVE-2025-12485 is a vulnerability classified under CWE-269 (Improper Privilege Management) affecting Devolutions Server versions 2025.3.2.0 through 2025.3.5.0 and earlier. The issue arises from improper handling of pre-MFA authentication cookies, which are used before multi-factor authentication is fully completed. A low-privileged authenticated user can replay these pre-MFA cookies to impersonate another user account. This impersonation does not bypass the MFA step of the target account, but it allows the attacker to assume the identity of another user within the system context that accepts the pre-MFA cookie. The vulnerability is remotely exploitable over the network without requiring user interaction, and it requires only low privileges, making it relatively easy for an attacker with some access to escalate privileges and move laterally. The impact includes full compromise of confidentiality, integrity, and availability of the affected system, as attackers can access sensitive data, modify configurations, or disrupt services. Although no public exploits are known yet, the high CVSS score of 8.8 indicates a critical risk. The vulnerability affects organizations relying on Devolutions Server for remote access and privileged account management, which are common in enterprise environments. The lack of patches at the time of publication necessitates immediate mitigation efforts. The flaw highlights the importance of secure session and cookie management, especially in pre-authentication phases of MFA workflows.

For European organizations, the impact of CVE-2025-12485 is significant due to the widespread use of Devolutions Server in managing remote access and privileged credentials. Successful exploitation could allow attackers to impersonate users, potentially gaining unauthorized access to critical systems and sensitive data. This can lead to data breaches, disruption of business operations, and compromise of network integrity. The vulnerability's ability to affect confidentiality, integrity, and availability simultaneously elevates the risk of severe operational and reputational damage. Organizations in sectors such as finance, government, healthcare, and critical infrastructure are particularly vulnerable, as they often rely on secure remote access solutions. The ease of exploitation without user interaction and the requirement of only low privileges increase the likelihood of internal threat actors or compromised accounts being leveraged for attacks. Additionally, the vulnerability could facilitate lateral movement within networks, enabling attackers to escalate privileges and expand their foothold. The absence of known exploits in the wild provides a window for proactive defense, but the high CVSS score demands urgent attention.

1. Immediate upgrade to a patched version of Devolutions Server once available, as no patches are currently provided. 2. Implement strict network segmentation and access controls to limit the ability of low-privileged users to access the Devolutions Server environment. 3. Monitor authentication logs and pre-MFA cookie usage patterns for anomalies indicative of replay attacks or impersonation attempts. 4. Enforce strong session management policies, including short session lifetimes and binding sessions to client attributes to reduce cookie replay risks. 5. Employ additional layers of authentication and authorization checks beyond cookie validation during the pre-MFA phase. 6. Conduct regular security audits and penetration testing focused on authentication mechanisms and privilege escalation vectors. 7. Educate administrators and users about the risks of credential reuse and the importance of reporting suspicious activities promptly. 8. Use endpoint detection and response (EDR) tools to identify lateral movement attempts following exploitation. 9. Restrict administrative privileges and implement the principle of least privilege to minimize potential damage from compromised accounts. 10. Prepare incident response plans specifically addressing potential exploitation of authentication vulnerabilities.