CVE-2024-26211 is a heap-based buffer overflow vulnerability identified in the Windows Remote Access Connection Manager component of Microsoft Windows 10 Version 1809 (build 10.0.17763.0). This vulnerability is classified under CWE-122, indicating a heap-based buffer overflow condition. The flaw allows an attacker with limited privileges (low-level privileges) to execute a carefully crafted local attack that can trigger the overflow, leading to an elevation of privilege. Specifically, the vulnerability arises when the Remote Access Connection Manager improperly handles certain inputs, causing memory corruption on the heap. This corruption can be exploited to execute arbitrary code with elevated privileges, potentially allowing the attacker to gain SYSTEM-level access. The CVSS v3.1 base score is 7.8 (high severity), reflecting high impact on confidentiality, integrity, and availability (all rated high), with an attack vector limited to local access (AV:L), low attack complexity (AC:L), and requiring low privileges (PR:L) but no user interaction (UI:N). The scope remains unchanged (S:U). No known exploits are currently reported in the wild, and no official patches are linked yet, though the vulnerability was published on April 9, 2024. The vulnerability is significant because it enables privilege escalation from a low-privileged user context to full system control, which can be leveraged by attackers to bypass security controls and execute further malicious activities on affected systems.

For European organizations, this vulnerability poses a substantial risk, especially in environments where Windows 10 Version 1809 is still in use, such as legacy systems in industrial control, healthcare, or government sectors. Successful exploitation can lead to full system compromise, allowing attackers to access sensitive data, disrupt operations, or deploy ransomware and other malware. The elevation of privilege aspect means that even users or malware with limited access can escalate their privileges, increasing the threat surface. This is particularly critical for organizations with strict data protection requirements under GDPR, as unauthorized access or data breaches could lead to regulatory penalties. Additionally, the vulnerability could be exploited to undermine endpoint security solutions running with lower privileges, facilitating persistent threats. Since the attack vector is local, insider threats or attackers who have gained initial footholds via other means (e.g., phishing) could leverage this vulnerability to deepen their access. The lack of user interaction required further increases the risk of automated exploitation in compromised environments.

1. Immediate mitigation should focus on identifying and isolating systems running Windows 10 Version 1809 (build 10.0.17763.0) to prioritize patching once available. 2. Until patches are released, restrict local access to sensitive systems by enforcing strict access controls and monitoring for unusual local activity, especially related to Remote Access Connection Manager processes. 3. Employ application whitelisting and endpoint detection and response (EDR) solutions configured to detect anomalous privilege escalation attempts and heap corruption indicators. 4. Harden user privileges by minimizing the number of users with local access and enforcing the principle of least privilege. 5. Use network segmentation to limit lateral movement from compromised hosts. 6. Monitor system logs and security events for signs of exploitation attempts, such as unexpected process launches or memory corruption alerts. 7. Educate users and administrators about the risks of local privilege escalation vulnerabilities and the importance of timely patching. 8. Consider upgrading affected systems to newer supported Windows versions where this vulnerability is not present or has been patched. 9. Implement strict control over software installation and execution to prevent introduction of malicious code that could exploit this vulnerability.