CVE-2025-55691 is a use-after-free vulnerability classified under CWE-416 that affects the Windows PrintWorkflowUserSvc service in Microsoft Windows 11 Version 25H2 (build 10.0.26200.0). This vulnerability arises from improper memory management where the service attempts to use memory after it has been freed, leading to undefined behavior. An authorized attacker with local access and limited privileges can exploit this flaw to execute arbitrary code in the context of a higher-privileged process, effectively elevating their privileges on the system. The attack complexity is high, requiring specific conditions to trigger the vulnerability, but no user interaction is needed once local access is obtained. The vulnerability impacts confidentiality, integrity, and availability by potentially allowing attackers to gain administrative control, access sensitive data, or disrupt system operations. Although no public exploits have been reported yet, the vulnerability's presence in a core Windows service that handles print workflows makes it a significant risk, especially in enterprise environments where printing services are widely used. The CVSS v3.1 base score of 7.0 reflects the high severity, with attack vector local, attack complexity high, privileges required low, and no user interaction. The vulnerability was reserved in August 2025 and published in October 2025, with no patches currently listed, indicating that organizations must monitor for updates and apply them promptly once available.

For European organizations, the impact of CVE-2025-55691 can be substantial. Many enterprises rely heavily on Windows 11 for their desktop and workstation environments, including critical sectors such as finance, healthcare, government, and manufacturing. The ability for a local attacker to escalate privileges can lead to unauthorized access to sensitive information, disruption of business-critical printing workflows, and potential lateral movement within networks. This could result in data breaches, operational downtime, and compliance violations under regulations like GDPR. Organizations with large numbers of users having local access to Windows 11 systems are particularly vulnerable. Additionally, environments that use print services extensively, such as office settings and public institutions, may face increased risk. The lack of known exploits currently provides a window for proactive defense, but the high severity and potential for privilege escalation necessitate urgent attention to mitigate risks before exploitation occurs.

1. Monitor Microsoft security advisories closely and apply official patches for Windows 11 Version 25H2 as soon as they are released to address CVE-2025-55691. 2. Restrict local access to systems running Windows 11 25H2 by enforcing strict access controls and limiting the number of users with local login privileges. 3. Implement application whitelisting and endpoint protection solutions that can detect anomalous behavior related to print services and privilege escalation attempts. 4. Audit and monitor print workflow services and related logs for unusual activity that may indicate exploitation attempts. 5. Use Group Policy to limit or disable unnecessary print services or features if feasible in the organizational context. 6. Educate IT staff and users about the risks of local privilege escalation vulnerabilities and the importance of reporting suspicious system behavior. 7. Employ network segmentation to isolate critical systems and reduce the impact of a compromised workstation. 8. Consider deploying enhanced memory protection technologies available in Windows 11, such as Control Flow Guard and Memory Integrity, to mitigate exploitation of use-after-free vulnerabilities.