CVE-2024-26244 is a high-severity remote code execution vulnerability affecting the Microsoft Windows 10 Version 1809 operating system, specifically targeting the Windows Defender Application Control (WDAC) OLE DB provider for SQL Server. The underlying issue is an integer underflow (CWE-191), which occurs when an arithmetic operation results in a value smaller than the minimum representable integer, causing a wraparound or unexpected behavior. This vulnerability can be exploited remotely without requiring privileges (PR:N) but does require user interaction (UI:R), such as opening a specially crafted file or link. The attacker can leverage this flaw to execute arbitrary code on the affected system with high impact on confidentiality, integrity, and availability. The CVSS 3.1 base score is 8.8, indicating a high severity level. The attack vector is network-based (AV:N), and the attack complexity is low (AC:L), meaning exploitation is feasible in typical environments. The scope is unchanged (S:U), so the vulnerability affects only the vulnerable component without extending to other system components. No known exploits are currently reported in the wild, and no official patches have been linked yet. The vulnerability's exploitation could allow attackers to bypass security controls implemented by WDAC, potentially leading to full system compromise on Windows 10 Version 1809 machines running the vulnerable OLE DB provider for SQL Server. Given the age of Windows 10 Version 1809 (released in late 2018), many organizations may have already moved to newer versions, but legacy systems remain at risk. The vulnerability's reliance on user interaction suggests social engineering or phishing vectors may be used to trigger the exploit.

For European organizations, this vulnerability poses a significant risk, especially for those still operating legacy Windows 10 Version 1809 systems in critical infrastructure, government, finance, healthcare, and industrial sectors. Successful exploitation could lead to remote code execution, enabling attackers to gain unauthorized access, deploy malware, exfiltrate sensitive data, disrupt operations, or pivot within networks. The high impact on confidentiality, integrity, and availability could result in data breaches, operational downtime, and reputational damage. Organizations relying on SQL Server with WDAC enabled are particularly vulnerable. Since the attack requires user interaction, phishing campaigns targeting European employees could be an effective attack vector. The lack of known exploits in the wild currently reduces immediate risk but does not eliminate the threat, as proof-of-concept exploits may emerge. The persistence of Windows 10 Version 1809 in certain sectors, especially in industrial control systems or legacy applications, increases the potential attack surface. Additionally, European GDPR regulations impose strict data protection requirements, so exploitation leading to data breaches could result in severe regulatory penalties.

1. Prioritize upgrading or patching all Windows 10 Version 1809 systems to a supported and updated Windows version where this vulnerability is resolved. 2. Until patches are available, disable or restrict the use of the WDAC OLE DB provider for SQL Server if feasible, or apply application whitelisting and strict execution policies to limit exposure. 3. Implement robust email filtering and user awareness training to reduce the risk of phishing attacks that could trigger the required user interaction. 4. Monitor network traffic and endpoint behavior for unusual activity related to SQL Server and WDAC components, including unexpected process launches or network connections. 5. Employ endpoint detection and response (EDR) solutions capable of detecting exploitation attempts involving integer underflow or anomalous OLE DB provider usage. 6. Enforce the principle of least privilege for users and services interacting with SQL Server and WDAC to minimize potential impact. 7. Conduct regular vulnerability scans and penetration tests focusing on legacy systems to identify and remediate similar risks. 8. Prepare incident response plans specific to remote code execution scenarios involving Windows 10 legacy components.