CVE-2025-49723 is a high-severity vulnerability identified in Microsoft Windows 10 Version 1809 (build 10.0.17763.0) involving a missing authorization check in the Windows StateRepository API. The StateRepository API is responsible for managing state data related to applications and system components. The vulnerability is classified under CWE-862, which indicates a missing authorization issue, meaning that the API fails to properly verify whether a user or process has the necessary permissions before allowing certain operations. This flaw allows an attacker with authorized local access (i.e., a user with some level of privileges on the affected system) to perform unauthorized tampering with the state repository data. The CVSS 3.1 base score is 8.8, reflecting a high severity due to the potential for complete compromise of confidentiality, integrity, and availability of the affected system components. The attack vector is local (AV:L), requiring low attack complexity (AC:L) and low privileges (PR:L), but no user interaction (UI:N). The scope is changed (S:C), indicating that the vulnerability can affect resources beyond the initially vulnerable component. The impact metrics are high for confidentiality, integrity, and availability (C:H/I:H/A:H). Although no known exploits are reported in the wild yet, the vulnerability poses a significant risk because it allows an attacker to tamper with critical system state data, potentially leading to privilege escalation, persistent malware installation, or disruption of system operations. No patches or mitigation links are currently provided, indicating that organizations must be vigilant and prepare for remediation once available.

For European organizations, this vulnerability presents a serious risk, especially in environments where Windows 10 Version 1809 is still in use. The ability for an attacker with local access and limited privileges to tamper with system state data can lead to unauthorized elevation of privileges, data corruption, or denial of service. Critical infrastructure, government agencies, financial institutions, and enterprises relying on legacy Windows 10 systems could face operational disruptions, data breaches, or compliance violations under GDPR if sensitive data integrity or availability is compromised. The vulnerability's exploitation could facilitate lateral movement within networks, increasing the risk of broader compromise. Given the high impact on confidentiality, integrity, and availability, organizations may experience significant downtime, data loss, and reputational damage if exploited.

1. Immediate mitigation should focus on restricting local access to systems running Windows 10 Version 1809, ensuring that only trusted users have login privileges. 2. Implement strict access controls and monitoring on endpoints to detect unusual local activities that may indicate exploitation attempts. 3. Employ application whitelisting and endpoint detection and response (EDR) solutions to identify and block unauthorized tampering with system APIs. 4. Since no official patch is currently available, organizations should consider upgrading affected systems to a supported and patched Windows version where this vulnerability is resolved. 5. Conduct regular audits of user privileges and remove unnecessary local accounts or privileges to reduce the attack surface. 6. Prepare incident response plans specifically addressing local privilege escalation and tampering scenarios. 7. Monitor official Microsoft security advisories closely for patch releases or workarounds related to CVE-2025-49723 and apply them promptly.