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, leading to a scenario where previously freed memory is accessed, potentially allowing an attacker to execute arbitrary code or escalate privileges. The flaw requires an attacker to have authorized local access with low privileges, but does not require user interaction, increasing the risk of stealthy exploitation. The vulnerability has a CVSS v3.1 base score of 7.0, indicating high severity, with attack vector local (AV:L), attack complexity high (AC:H), privileges required low (PR:L), no user interaction (UI:N), and impacts confidentiality, integrity, and availability (C:H/I:H/A:H). Although no known exploits are currently reported in the wild, the potential for privilege escalation to SYSTEM level makes this a critical concern for system security. The vulnerability affects the PrintWorkflowUserSvc, a service responsible for managing print workflows, which is a core component in Windows 11 for handling printing tasks. Exploitation could allow attackers to bypass security boundaries and gain elevated privileges, enabling further malicious activities such as installing malware, stealing sensitive data, or disrupting system operations. The vulnerability was reserved in August 2025 and published in October 2025, with no patches currently available, underscoring the need for proactive mitigation strategies.

For European organizations, this vulnerability poses a significant risk due to the widespread adoption of Windows 11 25H2 in enterprise environments. Successful exploitation could lead to unauthorized privilege escalation, allowing attackers to gain SYSTEM-level access, which compromises the confidentiality, integrity, and availability of critical systems and data. This could facilitate lateral movement within networks, deployment of ransomware, or data exfiltration. Organizations in sectors such as finance, healthcare, government, and critical infrastructure are particularly vulnerable due to the sensitive nature of their data and the potential impact of operational disruptions. The requirement for local access limits remote exploitation but does not eliminate risk, especially in environments with many users or where endpoint security is weak. The absence of known exploits currently provides a window for mitigation, but the high severity score and potential impact necessitate urgent attention to prevent future attacks.

1. Implement strict access controls to limit local user permissions, ensuring only trusted users have access to systems running Windows 11 25H2. 2. Monitor and audit the PrintWorkflowUserSvc service for unusual activity or crashes that could indicate exploitation attempts. 3. Employ application whitelisting and endpoint detection and response (EDR) solutions to detect and block suspicious behavior related to privilege escalation. 4. Isolate critical systems and restrict local administrative access to reduce the attack surface. 5. Prepare for rapid deployment of official patches from Microsoft once released by establishing a robust patch management process. 6. Educate IT staff and users about the risks of local privilege escalation vulnerabilities and the importance of maintaining strong endpoint security hygiene. 7. Consider disabling or restricting the PrintWorkflowUserSvc service where printing workflows are not essential or can be managed through alternative means. 8. Conduct regular vulnerability assessments and penetration testing to identify and remediate potential exploitation vectors related to this vulnerability.