CVE-2025-55686 is a use-after-free vulnerability classified under CWE-416 found in the Windows PrintWorkflowUserSvc service of Microsoft Windows 11 Version 25H2 (build 10.0.26200.0). This vulnerability arises when the service improperly manages memory, freeing an object while it is still in use, which can be exploited by an authorized local attacker to execute arbitrary code with elevated privileges. The attacker must have low-level privileges on the system but does not require user interaction to exploit the flaw. The vulnerability impacts confidentiality, integrity, and availability, as it allows privilege escalation to SYSTEM or equivalent high-level privileges. The CVSS v3.1 score is 7.0, indicating high severity, with vector metrics AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H, meaning the attack requires local access, high attack complexity, low privileges, no user interaction, unchanged scope, and results in high impact on confidentiality, integrity, and availability. No public exploits or patches are currently available, increasing the urgency for organizations to implement interim mitigations. The vulnerability specifically targets the PrintWorkflowUserSvc, a service related to print job processing workflows, which could be leveraged in environments with complex printing needs or shared workstations. Given the nature of the flaw, exploitation could allow attackers to bypass security controls and gain full control over affected systems.

For European organizations, this vulnerability poses a significant risk, particularly in sectors relying heavily on Windows 11 25H2, such as government, finance, healthcare, and critical infrastructure. Successful exploitation could lead to unauthorized access to sensitive data, disruption of printing services, and full system compromise, potentially enabling lateral movement within networks. The requirement for local access limits remote exploitation but does not eliminate risk, especially in environments with shared or poorly secured workstations. The high impact on confidentiality, integrity, and availability could result in data breaches, operational downtime, and reputational damage. The absence of known exploits currently provides a window for proactive defense, but the lack of patches means organizations must rely on compensating controls. The vulnerability could be leveraged in targeted attacks or insider threat scenarios, increasing risk for organizations with large user bases or complex printing infrastructures.

1. Restrict local access to Windows 11 25H2 systems, especially those running PrintWorkflowUserSvc, by enforcing strict access controls and least privilege principles. 2. Monitor event logs and system behavior for unusual activity related to the PrintWorkflowUserSvc or privilege escalation attempts. 3. Disable or restrict the PrintWorkflowUserSvc service on systems where printing workflows are not critical or can be managed differently. 4. Implement application whitelisting and endpoint detection and response (EDR) solutions to detect and block exploitation attempts. 5. Educate users and administrators about the risk of local privilege escalation vulnerabilities and the importance of securing local accounts. 6. Prepare for rapid deployment of official patches once released by Microsoft by maintaining an up-to-date asset inventory and patch management process. 7. Segment networks to limit lateral movement from compromised local accounts. 8. Employ multi-factor authentication (MFA) for local logins where possible to reduce risk of unauthorized access.