Researcher Archives

Winsage

June 3, 2026

Unpatched Windows Search URI Vulnerability Lets Attackers Steal NTLMv2 Hashes

Cybersecurity researchers have identified an unpatched vulnerability that could expose NTLMv2 hashes to attackers, linked to the "search:" URI handler. This issue is similar to CVE-2026-33829, which involved a spoofing vulnerability in the Windows Snipping Tool's ms-screensketch: URI handler. The flaw allows attackers to trick users into connecting to their SMB servers, disclosing NTLMv2 hashes for authentication exploitation. The new vulnerability operates using "search:" and "crumb=location:" parameters, resulting in a similar Net-NTLMv2 leak. Microsoft has chosen not to address this issue, stating only vulnerabilities classified as Important or Critical would be fixed. Recommendations to mitigate risks include blocking outbound SMB traffic, enforcing SMB signing, and disabling NTLM authentication where possible.

Winsage

June 1, 2026

Windows Server vulnerability can grant system privileges with just a malformed packet — domain controllers are being exploited in the wild

Microsoft is facing scrutiny due to a critical remote execution vulnerability, CVE-2026-41089, rated at 9.8, affecting Windows Server domain controllers from version 2012 onward. This vulnerability allows unauthenticated users on the same network to send malformed UDP packets to a domain controller, potentially granting unauthorized system access or causing a reboot, leading to denial-of-service scenarios. The vulnerable service is Netlogon, and there are no immediate mitigations available; patches will be released on May 12. The vulnerability could allow attackers to create multiple accounts with various access levels, compromising the security of entire networks. Cybersecurity experts recommend patching all linked domain controllers simultaneously. The vulnerability is caused by a buffer overflow in the Netlogon service due to a field in a network packet exceeding its expected size. A GitHub repository exists with proof-of-concept code that can crash the LSASS service. Additionally, Microsoft is in conflict with security researcher Chaotic Eclipse, who has published zero-day exploits following a breakdown in negotiations.

Winsage

June 1, 2026

Critical Windows Netlogon RCE flaw now exploited in attacks

The Centre for Cybersecurity Belgium (CCB) has warned about the exploitation of a critical vulnerability in Windows Netlogon, identified as CVE-2026-41089, which allows remote code execution on domain controllers without prior access or authentication. This vulnerability, characterized as a stack-based buffer overflow, was patched by Microsoft during the May 2026 Patch Tuesday. The CCB emphasized the urgency of patching vulnerable servers, noting that the vulnerability is actively being exploited. The CVSS score for this vulnerability is 9.8. Further details on the ongoing attacks have not been disclosed, and Microsoft has not updated its advisory on the vulnerability.

Winsage

May 29, 2026

Microsoft 0-day feud escalates as researcher threatens another Windows exploit dump

The conflict between Microsoft and security researcher Nightmare Eclipse has intensified, with Nightmare threatening to release vulnerabilities on July 14. Nightmare has disclosed six zero-day vulnerabilities affecting Windows, including BlueHammer, RedSun, UnDefend, YellowKey, GreenPlasma, and MiniPlasma. Microsoft responded by stating that these vulnerabilities were not reported through official channels before their disclosure. Following the release of exploit code for three vulnerabilities, attackers began exploiting them, raising concerns about YellowKey (CVE-2026-45585), which remains unfixed. Nightmare accused Microsoft of silencing them by deleting their MSRC account, leading to frustration over their treatment. The cybersecurity community has noted the significant damage caused by Nightmare, with comparisons to advanced persistent threat groups. Experts criticized Microsoft's handling of the situation, emphasizing the need for better communication and collaboration with researchers. They pointed out that the responsibility for vulnerabilities lies with Microsoft as the code's creator and highlighted the challenges in vulnerability disclosure practices within the industry.

Winsage

May 28, 2026

“I have proof for every single word”: This security researcher’s GitHub and Microsoft accounts were deleted after claiming a Windows 11 exploit in BitLocker is by design

A zero-day exploit named YellowKey was revealed by a researcher known as "Chaotic Eclipse" or Nightmare-Eclipse, which allows access to BitLocker-protected drives on Windows 11 using a USB key. Microsoft acknowledged the vulnerability, tracked as CVE-2026-45585, and provided mitigation strategies. The researcher expressed frustration over Microsoft's handling of the situation, including the banning of their GitHub account and lack of communication regarding unpaid bounties from Microsoft's MSRC program, which offers rewards for reporting vulnerabilities. Nightmare-Eclipse hinted at having evidence to support their claims and indicated plans to release documents related to the issue.

Winsage

May 28, 2026

Microsoft’s GitHub bans security researcher who posted zero-day Windows exploits because company ‘ruined their life’ — expert claims action is vindictive and promises further retaliation

Researcher Nightmare-Eclipse, also known as Chaotic Eclipse, has had their GitHub account banned by Microsoft, leading them to move their operations to GitLab. Microsoft also deleted Eclipse's Microsoft account used for reporting vulnerabilities. Eclipse claims that they have not received any financial rewards from Microsoft's bug bounty program, despite having reported multiple zero-day vulnerabilities. They possess a portfolio of six zero-day exploits and have hinted at revealing more on July 14. Eclipse has criticized Microsoft for their handling of vulnerability reports and suggested that the company's recent requirement for video evidence of exploits has contributed to tensions. Microsoft has not commented on the specifics of the situation. Eclipse's zero-day exploits include BlueHammer, RedSun, UnDefend, GreenPlasma, MiniPlasma, and YellowKey, with BlueHammer, RedSun, and UnDefend confirmed as actively exploited in the wild.

Winsage

May 25, 2026

Windows zero-days expose gaps in built-in security protections

Two Windows zero-day vulnerabilities, YellowKey and GreenPlasma, have been identified. YellowKey targets the Windows Recovery Environment (WinRE) on Windows 11 and Windows Server 2025, allowing attackers with physical access to bypass BitLocker protections using a USB device. GreenPlasma affects Windows 10, Windows 11, and Windows Server environments with active Collaborative Translation Framework Monitor (CTFMON) sessions, enabling local privilege escalation from a standard user account to SYSTEM-level privileges. Both vulnerabilities require either physical or local access to exploit. Microsoft has not yet released patches for these vulnerabilities, prompting organizations to enhance their security measures and operational resilience. Recommendations include reassessing physical security, limiting local administrative access, and implementing multifactor authentication and robust credential management practices.

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.

Winsage

May 22, 2026

Microsoft says public sharing of Windows 11 vulnerability violates ‘best practices’

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."

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.