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CVE-2026-45585: YellowKey BitLocker Bypass
Winsage
May 23, 2026

CVE-2026-45585: YellowKey BitLocker Bypass

BitLocker, a security feature for data protection, has a vulnerability identified as CVE-2026-45585, also known as YellowKey, which allows unauthorized access to encrypted data on Windows 11 versions 24H2, 25H2, 26H1, and Windows Server 2025. This flaw does not compromise BitLocker’s encryption but affects the recovery environment supporting it. The vulnerability can be exploited locally through the Windows Recovery Environment (WinRE) by an attacker with physical access, who can trigger an unrestricted shell and access the BitLocker-protected volume. Microsoft has provided two mitigation strategies: modifying the WinRE image to remove the autofstx.exe entry and transitioning from TPM-only protection to a TPM+PIN requirement at startup. The exploit poses challenges for detection, as it occurs pre-boot and currently lacks vendor-published indicators of compromise. Organizations using BitLocker for unattended devices are particularly at risk, as the vulnerability can lead to loss of confidentiality if an attacker gains access before the legitimate user.
Microsoft confirms two major Defender security issues — so update now or face possible attack
Tech Optimizer
May 22, 2026

Microsoft confirms two major Defender security issues — so update now or face possible attack

Microsoft has addressed two critical zero-day vulnerabilities in its Defender antivirus software: CVE-2026-41091 (privilege escalation) and CVE-2026-45498 (denial of service). The patches were delivered through Malware Protection Engine version 1.1.26040.8 and Antimalware Platform version 4.18.26040.7. Users are advised to verify their software versions to ensure they have the latest updates. Both vulnerabilities have been included in the Cybersecurity and Infrastructure Security Agency's Known Exploited Vulnerabilities catalog, requiring federal agencies to patch them or stop using the affected software by June 3.
Microsoft Defender Zero-Day Vulnerabilities RedSun and UnDefend Actively Exploited on Windows 10, 11, and Server (April 2026 CVE Analysis)
Winsage
May 21, 2026

Microsoft Defender Zero-Day Vulnerabilities RedSun and UnDefend Actively Exploited on Windows 10, 11, and Server (April 2026 CVE Analysis)

In April 2026, two zero-day vulnerabilities, RedSun and UnDefend, were discovered in Microsoft Defender, affecting Windows 10, Windows 11, and Windows Server platforms. These vulnerabilities allow attackers to escalate privileges to SYSTEM and bypass Defender’s protections. RedSun exploits a flaw in Defender's remediation process, enabling low-privileged users to overwrite critical system files. UnDefend allows attackers to disrupt Defender’s updates, keeping it outdated and ineffective. Both vulnerabilities are actively being exploited, with attackers leveraging them to gain persistent access and deploy ransomware. The primary targets are organizations using Windows systems with Defender enabled, particularly in sectors like finance, healthcare, and government. Mitigation strategies include applying updates for related vulnerabilities, monitoring for suspicious activities, and implementing additional security measures.
Microsoft shares mitigation for YellowKey Windows zero-day
Winsage
May 20, 2026

Microsoft shares mitigation for YellowKey Windows zero-day

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.
How To Mitigate The Microsoft Windows BitLocker ‘Angry Hacker’ 0-Day
Winsage
May 20, 2026

How To Mitigate The Microsoft Windows BitLocker ‘Angry Hacker’ 0-Day

Microsoft is addressing a zero-day exploit known as YellowKey, identified as CVE-2026-45585, which allows attackers to bypass BitLocker security using a specially crafted USB device. Following the release of exploit code by a hacker named Chaotic Eclipse, Microsoft has issued urgent mitigation advice. Cybersecurity expert Neena Sharma recommends treating this as an active threat and suggests implementing compensating controls, such as restricting USB boot access, until a patch is available. Microsoft has provided guidance for users to protect their systems, including the recommendation to add a PIN to BitLocker protection to reduce the risk of exploitation. Detailed instructions for adding a PIN are included in the advisory. YellowKey has not yet been exploited in the wild but requires physical access to the device.
MiniPlasma zero-day gives SYSTEM access on fully patched Windows 11
Winsage
May 18, 2026

MiniPlasma zero-day gives SYSTEM access on fully patched Windows 11

GitHub has introduced enhancements aimed at improving security and user experience on its platform. Key features include a more robust authentication process to protect user accounts, improved monitoring tools for tracking changes and vulnerabilities in repositories, a streamlined interface for easier navigation, and new collaboration features such as integrated chat options and real-time updates. Additionally, GitHub has launched initiatives to encourage user feedback to ensure the enhancements meet the needs of its user base.
MiniPlasma Windows 0-Day Enables SYSTEM Privilege Escalation on Fully Patched Systems
Winsage
May 18, 2026

MiniPlasma Windows 0-Day Enables SYSTEM Privilege Escalation on Fully Patched Systems

Chaotic Eclipse has unveiled a proof-of-concept (PoC) for a Windows privilege escalation zero-day vulnerability, codenamed MiniPlasma, which targets the "cldflt.sys" component and could grant SYSTEM privileges on fully patched Windows systems. This vulnerability was initially reported to Microsoft by James Forshaw from Google Project Zero in September 2020. Although Microsoft was believed to have resolved it in December 2020 as part of CVE-2020-17103, further analysis indicates that the flaw remains unaddressed. Chaotic Eclipse demonstrated that the original PoC could still spawn a SYSTEM shell reliably on his machines. The vulnerability is believed to affect all versions of Windows, with confirmation that MiniPlasma opens a "cmd.exe" prompt with SYSTEM privileges on Windows 11 systems with the latest May 2026 updates, though it does not function on the latest Insider Preview Canary version. In December 2025, Microsoft addressed a separate privilege escalation flaw in the same component, identified as CVE-2025-62221, which had a CVSS score of 7.8 and was reportedly being exploited by threat actors.
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