On September 8, 2026, Microsoft disclosed a security vulnerability identified as CVE-2026-69449, related to a heap-based buffer overflow in the Windows BitLocker component, allowing authorized attackers to execute code on compromised machines. The vulnerability is classified as CWE-122, and is assessed as “Exploitation Less Likely.” It affects Windows 10, Windows 11, and Windows Server versions from 2012 to 2025. The fixes are included in cumulative updates KB5124008, KB5124012, KB5122878, and KB5122871. No public disclosure or observed exploitation occurred before the patch's release. The flaw allows for remote code execution through in-network attacks, primarily posing a risk to insiders. Affected systems include various versions of Windows 10, Windows 11, and Windows Server, applicable to both x64 and ARM64 architectures. Administrators should verify installed build numbers to ensure updates have been applied. The advisory does not specify which BitLocker code path is affected or the nature of the input that reaches the vulnerable buffer.