CVE-2024-35256 is a high-severity heap-based buffer overflow vulnerability (CWE-122) affecting Microsoft SQL Server 2017 (GDR), specifically version 14.0.0. The vulnerability resides in the SQL Server Native Client OLE DB Provider component, which is used to facilitate database connectivity and operations. This buffer overflow can be triggered remotely without requiring prior authentication, though it does require user interaction, such as the victim initiating a connection or query that exploits the flaw. Successful exploitation allows an attacker to execute arbitrary code on the affected system with the privileges of the SQL Server service account. The vulnerability impacts confidentiality, integrity, and availability, as it can lead to full system compromise, data theft, or denial of service. The CVSS v3.1 base score is 8.8, reflecting its high impact and ease of exploitation over the network with low attack complexity. No public exploits are known in the wild yet, but the vulnerability is publicly disclosed and patched status is not indicated, so organizations should prioritize remediation. The vulnerability was reserved in May 2024 and published in July 2024, indicating recent discovery and disclosure.

For European organizations, this vulnerability poses a significant risk due to the widespread use of Microsoft SQL Server 2017 in enterprise environments for critical data storage and business applications. Exploitation could lead to unauthorized access to sensitive data, disruption of business operations, and potential lateral movement within corporate networks. Industries such as finance, healthcare, manufacturing, and public sector entities that rely heavily on SQL Server databases are particularly at risk. The remote code execution capability means attackers can compromise systems without physical access, increasing the threat surface. Given the high confidentiality, integrity, and availability impact, successful attacks could result in data breaches, regulatory non-compliance (e.g., GDPR violations), financial losses, and reputational damage.

European organizations should immediately assess their SQL Server 2017 deployments, focusing on version 14.0.0, and apply the latest security updates or patches provided by Microsoft as soon as they become available. In the absence of a patch, organizations should implement network-level controls to restrict access to SQL Server instances, such as firewall rules limiting inbound traffic to trusted IP addresses and VPN-only access. Employing application-layer firewalls or intrusion prevention systems (IPS) with signatures targeting this vulnerability can help detect and block exploit attempts. Additionally, organizations should audit and monitor SQL Server logs for unusual activity, enforce the principle of least privilege on SQL Server service accounts, and disable or restrict the use of the Native Client OLE DB Provider if not required. Regular vulnerability scanning and penetration testing should include checks for this vulnerability. User awareness training to avoid interacting with suspicious database queries or connections can reduce risk from social engineering vectors.