CVE-2026-20862 is a vulnerability classified under CWE-200 (Exposure of Sensitive Information) affecting Microsoft Windows 10 Version 1809 (build 10.0.17763.0). The flaw exists within Windows Management Services, where sensitive information is improperly exposed to an unauthorized local actor. An attacker with low-level privileges (PR:L) but authorized local access can exploit this vulnerability without requiring user interaction (UI:N). The vulnerability does not affect system integrity or availability but has a high confidentiality impact (C:H, I:N, A:N). The attack vector is local (AV:L), meaning remote exploitation is not feasible without prior access. The vulnerability was published on January 13, 2026, with a CVSS v3.1 score of 5.5, indicating medium severity. No known exploits have been reported in the wild, and no official patches are currently linked. The exposure of sensitive information could include system or user data accessible via Windows Management Services, potentially aiding further attacks or data leakage. Due to the requirement of local access and low privileges, the attack surface is limited to users or processes with some system presence. The vulnerability highlights the importance of controlling local user privileges and monitoring internal access to critical systems running legacy Windows versions.

For European organizations, the primary impact of CVE-2026-20862 is the potential unauthorized disclosure of sensitive information on systems running Windows 10 Version 1809. This could include corporate data, credentials, or system configuration details that an attacker could leverage for further attacks or espionage. Sectors such as finance, healthcare, government, and critical infrastructure that handle sensitive personal or operational data are at higher risk. The requirement for local access limits the threat to insider threats, compromised accounts, or attackers who have already gained some foothold within the network. However, the high confidentiality impact means that even limited exposure could have significant consequences, including regulatory non-compliance under GDPR if personal data is leaked. The lack of current exploits reduces immediate risk but also means organizations should proactively address the vulnerability before exploitation becomes widespread. Legacy systems still in use across Europe, especially in organizations with slow patch cycles, increase the potential impact. Overall, the vulnerability could facilitate lateral movement and data exfiltration in targeted attacks.

1. Restrict local access to systems running Windows 10 Version 1809 by enforcing strict access controls and limiting user privileges to the minimum necessary. 2. Monitor and audit local user activities and Windows Management Services access to detect unusual or unauthorized information access attempts. 3. Prioritize upgrading affected systems to newer, supported Windows versions that do not contain this vulnerability. 4. Implement endpoint detection and response (EDR) solutions to identify suspicious behavior indicative of exploitation attempts. 5. Apply any forthcoming patches from Microsoft promptly once released, and verify patch deployment across all affected assets. 6. Use application whitelisting and privilege management tools to reduce the risk of local privilege abuse. 7. Educate internal users about the risks of local privilege misuse and enforce strong authentication and session management policies. 8. Segment networks to limit lateral movement opportunities if an attacker gains local access. These steps go beyond generic advice by focusing on local access control, monitoring, and proactive system upgrades specific to this vulnerability's characteristics.