zero-day vulnerabilities Archives

Winsage

June 11, 2026

Nightmare Eclipse drops claimed BitLocker bypass for Microsoft Windows

Nightmare Eclipse has released a new zero-day vulnerability exploit called GreatXML, which allows unrestricted access to BitLocker volumes on Windows systems that have previously run a Microsoft Defender Offline scan. This discovery was made in four hours and adds to Nightmare Eclipse's total of eight zero-day vulnerabilities. Microsoft is investigating the claims related to another exploit, RoguePlanet, but has not commented on GreatXML or provided a patch timeline. Nightmare Eclipse, rumored to be a former Microsoft employee, has faced backlash from the security community for previous disclosures and has vowed to continue releasing vulnerabilities. Security expert Will Dormann has raised concerns about the practicality of the GreatXML exploit, noting that it requires administrative access and questioning the accuracy of the instructions provided by Nightmare.

Winsage

June 10, 2026

Microsoft’s biggest-ever Patch Tuesday fixes 206 bugs, including 3 zero-days

Microsoft's recent Patch Tuesday release addressed 206 security vulnerabilities, marking the largest update since the program began in October 2003. Among these, 32 vulnerabilities are classified as critical, including three zero-day vulnerabilities that were disclosed before patches were available, though none are reported to be actively exploited. Notable vulnerabilities include: - CVE-2026-50507 in Windows BitLocker, with a CVSS score of 6.8, allowing unauthorized bypass of security features through physical attacks. - CVE-2026-49160 in HTTP.sys, with a CVSS score of 7.5, which can be exploited for remote denial-of-service attacks. - CVE-2026-45586 in the Windows Collaborative Translation Framework (CTFMON), with a CVSS score of 7.8, which could grant SYSTEM privileges to attackers.

Winsage

June 10, 2026

Microsoft patches record 198 Windows bugs in June update – and 3 are zero days

Microsoft's latest Patch Tuesday addressed 198 security vulnerabilities, the most extensive update in recent memory. Among these, 32 flaws are classified as critical, and three are zero-day vulnerabilities. The updates are detailed in KB articles: KB5094126 for Windows 11 versions 24H2 and 25H2, KB5093998 for version 23H2, and KB5094127 for Windows 10. The updates will automatically download and install, but users must verify their installation status and reboot their computers for changes to take effect. The vulnerabilities addressed this month are attributed to advancements in artificial intelligence, with companies like Microsoft leveraging AI models to expedite the identification and resolution of security flaws. The three zero-day vulnerabilities include one that allows an attacker to gain Windows System privileges through a flaw in file link resolution, another that could facilitate a denial-of-service attack via an HTTP vulnerability, and a third related to a flaw in Windows BitLocker that could enable data capture from an unpatched PC. Additionally, the update introduces new features to Windows 11, including new Secure Boot certificates, a Low Latency Profile for enhanced performance, support for shared audio devices for multiple Bluetooth connections, webcam functionality across multiple applications, and the ability to assign a custom name to the user folder during setup.

Winsage

June 10, 2026

Windows 11’s June update shuts down an intentional BitLocker backdoor with full file access

Microsoft addressed three zero-day vulnerabilities identified by security researcher Nightmare-Eclipse, named YellowKey, GreenPlasma, and MiniPlasma. The YellowKey vulnerability allows access to BitLocker-protected drives on Windows 11 using a USB key, leading to allegations that Microsoft may have left a backdoor in BitLocker. Microsoft implemented a mitigation strategy included in the June 2026 Patch Tuesday updates, which addressed over 200 security flaws. Tensions arose between Microsoft and Nightmare-Eclipse regarding vulnerability reporting protocols and researcher compensation, with Microsoft initially threatening legal action against the researcher. Following backlash, Microsoft retracted the threat but tensions persisted. Nightmare-Eclipse claimed retaliation from Microsoft, including the banning of their GitHub account and deletion of their Microsoft account, which Microsoft denied. The situation highlights the ongoing challenges in cybersecurity and the relationship between tech companies and security researchers.

Tech Optimizer

June 5, 2026

Microsoft quietly deletes Windows 11 guide that claimed you don’t need third-party antivirus

In April 2026, a blog post from Microsoft's Windows Learning Center claimed that most Windows 11 users could rely solely on Windows Security (Defender) for antivirus protection, citing features like Microsoft Defender Antivirus, SmartScreen, and ransomware mitigation. The blog was later removed without explanation, leading to speculation about its definitive claims. Microsoft stated that Windows Defender was sufficient for typical users with default settings and regular updates, while cautioning against using multiple antivirus engines. Independent testing from AV-Test consistently ranks Microsoft Defender highly, but AV-Comparatives noted limitations in offline protection and the reliance on cloud-based intelligence. The blog's removal was viewed by some as a constructive step towards realistic security guidance. Microsoft continues to provide third-party antivirus vendors with significant access to Windows, and the rise of AI-generated threats is complicating the cybersecurity landscape. Despite the controversies, Microsoft has made significant advancements in Windows Security, making it a viable option for many users.

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

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.

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.

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.