CVE-2025-55331 is a use-after-free vulnerability classified under CWE-416 affecting the Windows PrintWorkflowUserSvc service in Microsoft Windows 11 Version 25H2 (build 10.0.26200.0). This vulnerability arises when the service improperly manages memory, allowing an attacker with authorized local access and low privileges to exploit the use-after-free condition to execute arbitrary code with elevated privileges. The flaw does not require user interaction but does require the attacker to have some level of local access, making remote exploitation infeasible without prior access. Successful exploitation can lead to full system compromise, impacting confidentiality, integrity, and availability of the affected system. The vulnerability has a CVSS v3.1 base score of 7.0, reflecting high severity due to the potential impact and the complexity of the attack. No public exploits or proof-of-concept code have been reported yet, but the vulnerability is officially published and reserved since August 2025. The lack of a patch at the time of publication means organizations must rely on mitigating controls until updates are released by Microsoft. The PrintWorkflowUserSvc is related to print workflow management, a component commonly enabled in Windows environments, increasing the attack surface. Given the nature of the vulnerability, attackers could leverage it to bypass security controls and gain administrative privileges, facilitating further lateral movement or persistence within a network.

For European organizations, this vulnerability poses a significant risk especially in environments where Windows 11 Version 25H2 is deployed. The ability for a low-privileged local user to escalate privileges can lead to unauthorized access to sensitive data, disruption of critical services, and potential full system compromise. This is particularly concerning for sectors with strict data protection requirements such as finance, healthcare, and government institutions. The vulnerability could be exploited by malicious insiders or through compromised endpoints where attackers gain initial foothold with limited privileges. The impact extends to confidentiality breaches, integrity violations through unauthorized code execution, and availability issues if attackers disrupt print services or system stability. Organizations with remote or hybrid work models may face increased risk if endpoint security is lax, as attackers could exploit compromised devices locally. The absence of known exploits in the wild provides a window for proactive defense, but the high severity score demands urgent attention to prevent exploitation.

Until an official patch is released by Microsoft, European organizations should implement specific mitigations: 1) Restrict local access to systems running Windows 11 Version 25H2, especially limiting access to trusted users only. 2) Employ application whitelisting and endpoint detection and response (EDR) solutions to monitor and block suspicious activity related to PrintWorkflowUserSvc or unusual privilege escalation attempts. 3) Harden user privileges by enforcing the principle of least privilege and removing unnecessary local administrative rights. 4) Monitor system logs and audit events for anomalies indicative of use-after-free exploitation or privilege escalation attempts. 5) Disable or restrict the PrintWorkflowUserSvc service if printing workflows are not critical to business operations, reducing the attack surface. 6) Prepare for rapid deployment of security updates once Microsoft releases patches by testing and validating updates in controlled environments. 7) Educate IT and security teams about this vulnerability to ensure timely detection and response. These targeted actions go beyond generic advice by focusing on the specific service and attack vector involved.