CVE-2024-35256 is a heap-based buffer overflow vulnerability classified under 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 responsible for database connectivity and data access. A heap-based buffer overflow occurs when the application writes more data to a buffer located on the heap than it can hold, potentially overwriting adjacent memory. This can lead to arbitrary code execution, allowing an attacker to run malicious code remotely. The vulnerability is exploitable over the network (AV:N), requires no privileges (PR:N), but does require user interaction (UI:R), such as convincing a user to connect to a malicious database or open a crafted file. The scope is unchanged (S:U), meaning the impact is limited to the vulnerable component. The CVSS v3.1 base score is 8.8, indicating high severity with high impact on confidentiality, integrity, and availability (C:H/I:H/A:H). No known exploits have been reported in the wild yet, but the vulnerability was reserved in May 2024 and published in July 2024, suggesting recent discovery. The lack of available patches at the time of reporting means organizations must rely on interim mitigations. The vulnerability could be leveraged to compromise database servers, leading to data breaches, service disruption, or lateral movement within networks.

For European organizations, this vulnerability poses a significant risk due to the widespread use of Microsoft SQL Server 2017 in enterprise environments, including critical sectors such as finance, healthcare, government, and manufacturing. Successful exploitation could lead to unauthorized access to sensitive data, disruption of database services, and potential full system compromise. This would impact data confidentiality, integrity, and availability, potentially causing regulatory non-compliance under GDPR and other data protection laws. The requirement for user interaction slightly reduces the risk but does not eliminate it, especially in environments where users frequently interact with database clients or open external data sources. The absence of known exploits currently provides a window for proactive defense, but the high CVSS score indicates that once exploits emerge, the threat will be severe. Disruption of SQL Server services could also affect business continuity and critical infrastructure operations across Europe.

1. Monitor Microsoft security advisories closely and apply official patches immediately once released for SQL Server 2017 (GDR) version 14.0.0. 2. Restrict network access to SQL Server instances using firewalls and network segmentation, allowing only trusted hosts and users. 3. Implement strict access controls and least privilege principles for database users and applications. 4. Educate users about the risks of interacting with untrusted data sources or opening unknown files that could trigger the vulnerability. 5. Employ intrusion detection and prevention systems (IDS/IPS) to monitor for anomalous SQL Server traffic or exploitation attempts. 6. Regularly audit and harden SQL Server configurations, disabling unnecessary features such as the Native Client OLE DB Provider if not required. 7. Use application whitelisting and endpoint protection solutions to detect and block suspicious code execution. 8. Prepare incident response plans specific to database compromise scenarios to minimize impact if exploitation occurs.