Key Takeaways:
- Critical Windows BitLocker Zero Day Vulnerability
- YellowKey (Encryption Bypass) Exploits the Windows Recovery Environment (WinRE).
- Affects Windows 11, Server 2022, and Server 2025; Windows 10 is not impacted.
- GreenPlasma (Privilege Escalation) Targets the Windows CTFMON service via arbitrary memory section creation.
- Enables manipulation of trusted services and drivers to run unauthorized commands.
Let’s discuss Fix Critical Windows BitLocker Zero Day Vulnerability Allows Attackers to Bypass Encryption. Microsoft announced new unpatched zero-day vulnerabilities in Windows BitLocker. This new vulnerability significantlyhcompromise Microsoft’s ecosystem. There are 2 exploits are addressed which are critical BitLocker encryption bypass called YellowKey and a privilege escalation flaw named GreenPlasma.
Table of Contents
Table of Contents
Fix Critical Windows BitLocker Zero Day Vulnerability Allows Attackers to Bypass Encryption
After the patch Tuesday update, Due to this vulnerability, a frustrated researcher escalated an ongoing dispute by dropping two severe zero-day exploits. Millions of enterprise and government devices are now exposed. Researcher controversially claims these are intentional backdoors, even naming internal Microsoft threat groups.
- BitLocker Recovery Prompt Reported After April 2026 Windows Security Updates
- Secure Windows Devices with BitLocker Startup Authentication using Intune
- How to Deploy KB5061768 OOB Update for Windows 10 BitLocker Recovery Screen Issue using Intune
YellowKey BitLocker Bypass
Lets attackers with physical access bypass BitLocker full‑disk encryption in minutes. Exploits the Windows Recovery Environment (WinRE). Affects Windows 11, Server 2022, and Server 2025; Windows 10 is safe due to different recovery architecture. Attackers can either use a USB stick with a specially named FsTx folder. Or copy exploit files into the EFI partition of the drive. Once rebooted into recovery, the exploit spawns a shell with unrestricted access.
| Vulnerability Type | Affected Systems | Key Artifacts |
|---|---|---|
| Encryption Bypass | Windows 11, Server 2022/2025 | System Volume Information\FsTx directory |
| WinRE Exploit | Windows 11, Server 2022/2025 | bootmgfw.efi manipulation |
GreenPlasma Privilege Escalation
Targets the Windows CTFMON service via arbitrary memory section creation. Allows manipulation of trusted services and drivers to run unauthorized commands. Current proof‑of‑concept requires a UAC prompt, but with further weaponization it could become silent and persistent.
| Vulnerability Type | Affected Systems | Key Artifacts |
|---|---|---|
| Privilege Escalation | Windows 11, Server 2022/2025 | CTFMON Arbitrary Section Creation |
| Memory Manipulation | Windows 11, Server 2022/2025 | SYSTEM-writable directory objects |
Fix Availability
Microsoft has released a fix via the KB5089549 cumulative update, but only for Windows 11 25H2 systems. Windows 10 and Windows Server users must wait for a future update.
Temporary Workaround
Admins are advised to remove the “Configure TPM platform validation profile for native UEFI firmware configurations” Group Policy setting before deploying the April 2026 updates, and ensure BitLocker bindings use the PCR7 profile.
Note :- Windows 10 and Server users remain affected until a future patch. Admins should apply the workaround to avoid recovery prompts.
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Author
Anoop C Nair has been Microsoft MVP for 10 consecutive years from 2015 onwards. He is a Workplace Solution Architect with more than 22+ years of experience in Workplace technologies. He is a Blogger, Speaker, and Local User Group Community leader. His primary focus is on Device Management technologies like SCCM and Intune. He writes about technologies like Intune, SCCM, Windows, Cloud PC, Windows, Entra, Microsoft Security, Career, etc.