A security researcher known as Nightmare-Eclipse revealed a vulnerability in Windows 11, named YellowKey, which allows attackers to access BitLocker-encrypted drives through the Windows Recovery Environment. Microsoft acknowledged the vulnerability, assigned it the identifier CVE-2026-45585, and criticized the public sharing of its proof of concept. Currently, there is no patch available for the BitLocker bypass, but physical access to the device provides some protection. The vulnerability does not exist in Windows 10 due to differences in the Windows Recovery Environment. The attack requires a stolen Windows 11 laptop and a USB stick, and the vulnerable filesystems include NTFS, FAT32, and exFAT. Nightmare-Eclipse speculated that the bypass may function as a backdoor, while Microsoft referred to it as a "security feature bypass vulnerability."