Microsoft has addressed the YellowKey vulnerability, a zero-day flaw in Windows BitLocker identified as CVE-2026-45585. This vulnerability allows unauthorized access to BitLocker-protected drives through a specific exploitation process involving 'FsTx' files. The flaw was disclosed by an anonymous researcher known as 'Nightmare Eclipse.' Microsoft has released mitigation strategies, including removing the autofstx.exe entry from the Session Manager's BootExecute REGMULTISZ value and reestablishing BitLocker trust for WinRE. Additionally, users are advised to change BitLocker settings from "TPM-only" to "TPM+PIN" mode, requiring a pre-boot PIN for drive decryption, and to enable "Require additional authentication at startup" for unencrypted devices.