CVE-2024-26168 is a heap-based buffer overflow vulnerability (CWE-122) identified in Microsoft Windows 10 Version 1809 (build 10.0.17763.0). This vulnerability specifically affects the Secure Boot security feature, which is designed to ensure that only trusted software is loaded during the system startup process. The heap-based buffer overflow occurs when the system improperly handles certain data structures or inputs related to Secure Boot, potentially allowing an attacker to overwrite memory on the heap. This can lead to arbitrary code execution with elevated privileges, bypassing Secure Boot protections. The vulnerability does not require user interaction or privileges to exploit, but it does require local access (attack vector: physical or local access). The CVSS v3.1 base score is 6.8, indicating a medium severity level, with high impact on confidentiality, integrity, and availability if exploited. No known exploits are reported in the wild yet, and no patches have been linked at the time of publication. The vulnerability was reserved in February 2024 and published in April 2024. The lack of patches and known exploits suggests that organizations should prioritize mitigation and monitoring to prevent potential exploitation.

For European organizations, the impact of CVE-2024-26168 could be significant, especially in sectors relying heavily on Windows 10 Version 1809 systems with Secure Boot enabled, such as government, finance, healthcare, and critical infrastructure. Successful exploitation could allow attackers to bypass Secure Boot protections, leading to the execution of unauthorized code during system startup. This undermines the trustworthiness of the boot process, potentially enabling persistent malware infections, rootkits, or firmware-level compromises that are difficult to detect and remediate. Confidentiality, integrity, and availability of critical systems could be severely affected, leading to data breaches, operational disruptions, and loss of trust. Given that Windows 10 Version 1809 is an older release, some organizations may still use it due to legacy application dependencies, increasing their exposure. The absence of known exploits reduces immediate risk but does not eliminate the threat, as attackers may develop exploits over time. European organizations should be aware that this vulnerability could be leveraged in targeted attacks or supply chain compromises, especially where physical or local access is possible.

1. Upgrade or patch: Although no patches are linked currently, organizations should monitor Microsoft security advisories closely and apply any forthcoming security updates promptly. 2. Upgrade OS: Consider upgrading from Windows 10 Version 1809 to a more recent, supported Windows version that includes security improvements and patches for known vulnerabilities. 3. Secure physical access: Since exploitation requires local or physical access, enforce strict physical security controls to prevent unauthorized access to devices. 4. Harden Secure Boot configuration: Review and enforce Secure Boot policies and configurations to ensure they are not weakened or bypassed. 5. Endpoint detection and response (EDR): Deploy advanced endpoint monitoring tools capable of detecting anomalous behavior during boot or early system startup phases. 6. Network segmentation: Limit network exposure of vulnerable systems to reduce the attack surface. 7. Incident response readiness: Prepare for potential exploitation by establishing robust incident detection and response procedures focused on firmware and boot-level compromises. 8. Inventory and asset management: Identify all systems running Windows 10 Version 1809 to prioritize remediation efforts effectively.