CVE-2025-55691 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 objects while references to them remain accessible, which can be exploited by an authorized local attacker to execute arbitrary code or elevate privileges. The attacker must have low-level privileges on the system but does not require user interaction to exploit the flaw. The vulnerability affects confidentiality, integrity, and availability by potentially allowing attackers to gain SYSTEM-level privileges, thereby compromising the entire system. The CVSS v3.1 score of 7.0 indicates high severity, with attack vector local (AV:L), attack complexity high (AC:H), privileges required low (PR:L), no user interaction (UI:N), and scope unchanged (S:U). Although no public exploits are currently known, the vulnerability poses a significant risk to environments where Windows 11 25H2 is deployed, particularly in enterprise and government sectors relying on print workflow services. The vulnerability was reserved in August 2025 and published in October 2025, with no patches currently available, emphasizing the need for proactive mitigation strategies.

For European organizations, this vulnerability presents a critical risk due to the widespread adoption of Windows 11 in corporate and governmental environments. Exploitation could lead to unauthorized privilege escalation, enabling attackers to execute malicious code with SYSTEM privileges, potentially leading to data breaches, disruption of services, or full system compromise. Organizations with print workflow dependencies may face increased risk, as the vulnerability resides in the PrintWorkflowUserSvc service. The impact extends to confidentiality, integrity, and availability of critical systems, potentially affecting sensitive data and operational continuity. Given the high attack complexity and requirement for local access, the threat is more pronounced in environments with inadequate endpoint security, weak access controls, or insider threat risks. The absence of known exploits in the wild provides a window for mitigation but also underscores the urgency for patching once updates are released. Failure to address this vulnerability could result in significant operational and reputational damage, especially for sectors with stringent data protection regulations such as finance, healthcare, and public administration within Europe.

1. Monitor Microsoft security advisories closely and apply official patches immediately upon release to remediate the vulnerability. 2. Restrict local access to systems running Windows 11 Version 25H2, especially limiting administrative and print service permissions to trusted personnel only. 3. Implement strict endpoint security controls, including application whitelisting and behavior-based detection to identify anomalous privilege escalation attempts. 4. Harden print workflow services by disabling or restricting PrintWorkflowUserSvc where not required or isolating it within controlled environments. 5. Conduct regular audits of user privileges and system logs to detect early signs of exploitation or misuse. 6. Employ network segmentation to limit lateral movement in case of compromise. 7. Educate IT staff and users about the risks of local privilege escalation vulnerabilities and the importance of maintaining updated systems. 8. Prepare incident response plans that include scenarios involving local privilege escalation to ensure rapid containment and remediation.