Security researcher says Microsoft secretly built a backdoor into BitLocker, releases an exploit to prove it

Microsoft issued an emergency mitigation for a reported BitLocker flaw, now tracked as CVE-2026-45585, after a researcher published proof-of-concept exploits.

The exploit, called YellowKey, is claimed to bypass BitLocker on some Windows systems by abusing WinRE and a special FsTx folder on removable media or the EFI partition.

If validated, the issue could let an attacker with brief physical access defeat full-disk encryption and access protected data.

The researcher also disclosed GreenPlasma, a separate privilege-escalation exploit, adding to the security concerns around affected Windows versions.