CVE-2024-26209 is a medium-severity vulnerability identified in Microsoft Windows 10 Version 1809 (build 10.0.17763.0) affecting the Local Security Authority Subsystem Service (LSASS). The vulnerability is classified under CWE-908, which refers to the use of uninitialized resources. Specifically, this flaw arises when LSASS improperly handles memory resources that have not been initialized before use, potentially leading to information disclosure. An attacker with limited privileges (local access and low complexity attack vector) can exploit this vulnerability without requiring user interaction. Exploitation could allow the attacker to read sensitive information from memory that should otherwise be protected, impacting confidentiality. The CVSS v3.1 base score is 5.5, reflecting a medium severity level, with the vector indicating local attack vector (AV:L), low attack complexity (AC:L), requiring privileges (PR:L), no user interaction (UI:N), unchanged scope (S:U), high confidentiality impact (C:H), no integrity or availability impact (I:N/A:N). There are no known exploits in the wild at the time of publication, and no official patches have been linked yet. The vulnerability was reserved in February 2024 and published in April 2024. This issue is significant because LSASS is a critical Windows component responsible for enforcing security policies, and any information disclosure here could facilitate further attacks such as privilege escalation or lateral movement within a network.

For European organizations, this vulnerability poses a risk primarily to systems still running Windows 10 Version 1809, which, despite being an older release, may remain in use in certain environments due to legacy application dependencies or delayed upgrade cycles. The information disclosure could expose sensitive authentication tokens, credentials, or security policy data, potentially enabling attackers to escalate privileges or move laterally within corporate networks. This is particularly concerning for sectors with high-value targets such as finance, government, healthcare, and critical infrastructure, where confidentiality breaches can lead to significant operational, financial, and reputational damage. Since exploitation requires local access and privileges, the threat is more relevant in scenarios where attackers have already gained some foothold, such as through phishing or insider threats. The absence of user interaction lowers the barrier for exploitation once local access is obtained. The medium severity rating suggests that while the vulnerability is not immediately critical, it can be leveraged as part of a multi-stage attack chain, increasing overall risk. Organizations with strict compliance requirements under GDPR and other data protection regulations must consider the potential for data leakage and the associated legal and regulatory consequences.

Given the lack of an official patch at the time of analysis, European organizations should implement targeted mitigations beyond generic advice. First, they should prioritize upgrading affected systems from Windows 10 Version 1809 to a supported, fully patched Windows version to eliminate exposure. Where immediate upgrades are not feasible, organizations should enforce strict local access controls and limit administrative privileges to reduce the risk of exploitation. Employing endpoint detection and response (EDR) solutions with behavior-based detection can help identify suspicious LSASS-related activities indicative of exploitation attempts. Network segmentation should be enhanced to restrict lateral movement opportunities for attackers who gain local access. Additionally, organizations should audit and monitor privileged account usage closely and implement multi-factor authentication (MFA) to reduce the impact of credential exposure. Regular memory integrity checks and system integrity monitoring can help detect anomalies caused by exploitation. Finally, organizations should stay alert for official patches or advisories from Microsoft and apply them promptly once available.