zero-day vulnerability Archives

Winsage

April 18, 2026

‘They mopped the floor with me and pulled every childish game they could’: Disgruntled researcher releases second major Windows zero-day — claims Microsoft ‘would ruin my life, and they did’

A new zero-day vulnerability in Microsoft Defender has been disclosed by a researcher known as "Chaotic Eclipse," who has created a proof-of-concept exploit called "RedSun." This vulnerability allows local privilege escalation to SYSTEM level on Windows 10, Windows 11, and Windows Server when Microsoft Defender is active. The vulnerability has attracted attention from antivirus vendors, with some detecting it on VirusTotal due to an embedded EIRCAR in the executable. Chaotic Eclipse previously disclosed another vulnerability named BlueHammer, which also allowed local attackers to gain SYSTEM or elevated permissions. The researcher expressed dissatisfaction with Microsoft's vulnerability disclosure process, recounting negative interactions with the company. A Microsoft spokesperson stated the company's commitment to investigating security issues and supporting coordinated vulnerability disclosure.

Winsage

April 18, 2026

‘They mopped the floor with me and pulled every childish game they could’: Disgruntled researcher releases second major Windows zero-day — claims Microsoft ‘would ruin my life, and they did’

A researcher known as “Chaotic Eclipse” has revealed a new zero-day vulnerability in Microsoft Defender, called “RedSun,” which allows local privilege escalation to SYSTEM privileges on Windows 10, Windows 11, and Windows Server when Microsoft Defender is enabled. The exploit has been confirmed to function correctly, and some antivirus vendors have begun detecting it. This follows another vulnerability disclosure by the same researcher, named BlueHammer, which also allows local attackers to elevate permissions. Chaotic Eclipse expressed dissatisfaction with Microsoft’s handling of vulnerability disclosures, claiming they were threatened and experienced frustration with the company’s response. A Microsoft spokesperson stated the company is committed to investigating reported security issues and supports coordinated vulnerability disclosure.

Winsage

April 10, 2026

Windows Zero-Day Published on Github as Microsoft Fails to Act

A security researcher named Chaotic Eclipse published a working exploit for a Windows zero-day vulnerability, called BlueHammer, on GitHub on April 2. The exploit allows attackers to gain SYSTEM-level privileges by exploiting a race condition in Windows Defender’s signature update mechanism. The exploit has gained significant attention, with over 100 forks and nearly 300 stars on GitHub. Will Dormann, a principal vulnerability analyst, confirmed that while BlueHammer is functional, it may not always operate reliably. Microsoft has not issued a patch for this vulnerability. The exploit targets the Windows Defender signature update process, allowing low-privilege attackers to manipulate a file path during operation, leading to access to the Security Account Manager (SAM) database. Currently, only 8 out of 72 cybersecurity vendors on VirusTotal flag the exploit file as malicious, which raises concerns about detection coverage. Microsoft reiterated its commitment to coordinated vulnerability disclosure but did not address the communication issues regarding the BlueHammer report.

Winsage

April 7, 2026

Disgruntled researcher drops “BlueHammer” Windows zero-day LPE exploit

A security researcher, known as "Nightmare-Eclipse," released proof-of-concept exploit code for a Windows zero-day vulnerability called "BlueHammer," which allows local privilege escalation (LPE). The exploit has been validated by another researcher, Will Dormann, who confirmed it can escalate privileges on Windows systems, allowing non-administrative users to gain SYSTEM-level access. The exploit's reliability varies across different Windows versions, with inconsistent success rates reported. Microsoft has not acknowledged the vulnerability or provided a patch, raising concerns about potential exploitation by threat actors. Users are advised to restrict local user access, monitor for suspicious activity, and enable advanced endpoint protection.

Winsage

April 6, 2026

Disgruntled researcher leaks “BlueHammer” Windows zero-day exploit

Exploit code for a Windows privilege escalation vulnerability, named BlueHammer, has been released, allowing attackers to gain SYSTEM or elevated administrator permissions. This zero-day vulnerability was disclosed by a researcher, Chaotic Eclipse, who expressed frustration with Microsoft's handling of the issue. The exploit combines a time-of-check to time-of-use (TOCTOU) issue with path confusion, granting local attackers access to the Security Account Manager (SAM) database, which contains password hashes for local accounts. While the exploit is confirmed to work, it has been found unsuccessful on Windows Server due to bugs that hinder its effectiveness. Attackers can gain local access through various means, raising significant security risks. Microsoft has not yet responded to inquiries about the BlueHammer flaw.

Tech Optimizer

February 16, 2026

What is the best PC antivirus for 2026: Acronis True Image vs. competitors

In 2026, traditional antivirus solutions are becoming outdated due to the rise of sophisticated cyber threats, including AI-driven ransomware and advanced phishing schemes. The FBI Internet Crime Report states that cybercrime losses exceeded .5 billion in 2023, with projections by Cybersecurity Ventures estimating costs could reach trillion annually by 2025. Research from IBM shows that organizations without a tested recovery plan face higher costs and longer downtimes. Built-in protections like Windows Defender and MacOS XProtect offer basic security but may leave gaps, necessitating comprehensive third-party antivirus solutions. Acronis True Image is highlighted for its unique combination of real-time malware protection and full system backup capabilities, enabling users to recover quickly from incidents. Other leading antivirus solutions, such as Norton 360, Bitdefender, McAfee, and Kaspersky, excel in threat prevention but lack integrated recovery options. Acronis emphasizes the importance of both security and continuity, preparing users for both cyber incidents and everyday failures.

Winsage

February 11, 2026

Patch Tuesday, February 2026 Edition

Microsoft has released updates addressing over 50 vulnerabilities in its Windows operating systems and applications, including six critical zero-day vulnerabilities. 1. CVE-2026-21510: A security feature bypass in Windows Shell that allows execution of malicious content via a single click on a link, affecting all supported Windows versions. 2. CVE-2026-21513: Targets MSHTML, the web browser engine in Windows. 3. CVE-2026-21514: A security feature bypass in Microsoft Word. 4. CVE-2026-21533: Allows local attackers to gain SYSTEM level access in Windows Remote Desktop Services. 5. CVE-2026-21519: An elevation of privilege flaw in the Desktop Window Manager (DWM). 6. CVE-2026-21525: A potential denial-of-service threat in the Windows Remote Access Connection Manager. Additionally, the updates include fixes for remote code execution vulnerabilities affecting GitHub Copilot and various IDEs, specifically CVE-2026-21516, CVE-2026-21523, and CVE-2026-21256, which arise from a command injection flaw. Security experts emphasize the importance of safeguarding developers due to their access to sensitive data and recommend applying least-privilege principles.

Winsage

January 19, 2026

The Last Windows Security Updates of January 2026 Are Here

Microsoft released its first set of security updates for the Windows operating system and various products in January 2026, addressing over 110 vulnerabilities. The updates are available for all supported versions of Windows, with Windows 10 receiving fixes only through the Extended Security Updates (ESU) program. Windows 11 versions 24H2 and 25H2 are the main consumer releases benefiting from these updates. Approximately 112–114 security updates were released, with around 8 rated as Critical. At least one zero-day vulnerability is actively exploited. The updates include security fixes for Windows, Office, Edge, Azure, and server components. Windows 11 versions 23H2, 24H2, and 25H2, as well as Windows Server 2023 and 2025, have known issues. Windows 11 version 24H2 and 25H2 received security fixes for multiple vulnerabilities, while version 23H2 continues to receive support through enterprise servicing channels. Windows 10 updates are limited to ESU-enrolled systems, with general support ending in October 2025. Windows Server 2016, 2019, 2022, 2023, and 2025 received January security updates, addressing important vulnerabilities without disclosing any critical ones. Microsoft also released updates for Office products and SharePoint Server components. Known issues after the January updates include credential prompt failures and authentication issues in Azure Virtual Desktop and Windows 365, particularly affecting the new Windows App. Workarounds involve using the classic Remote Desktop client or the web-based RDP client. Additionally, devices with Secure Launch enabled may experience shutdown and sleep mode failures. Microsoft has provided out-of-band fixes for certain affected systems as of January 18, 2026. Users can manually install updates through the Windows Update feature, and it is recommended to create a full system backup before proceeding with updates.

Winsage

January 15, 2026

Windows info-disclosure 0-day bug gets a fix as CISA sounds alarm

Microsoft and the U.S. government have issued a warning about a vulnerability in Windows, designated CVE-2026-20805, which is currently being exploited. This flaw allows an authorized attacker to leak a memory address from a remote ALPC port, potentially leading to arbitrary code execution. It has a medium severity rating of 5.5 on the CVSS scale. The U.S. Cybersecurity and Infrastructure Security Agency (CISA) has added this vulnerability to its Known Exploited Vulnerabilities catalog and requires federal agencies to implement a patch by February 3. Additionally, two other vulnerabilities were acknowledged: CVE-2026-21265, a secure boot certificate expiration bypass with a CVSS rating of 6.4, and CVE-2023-31096, an elevation of privilege flaw affecting third-party Agere Modem drivers, rated at 7.8. Two more vulnerabilities, CVE-2026-20952 (CVSS 7.7) and CVE-2026-20953 (CVSS 7.4), are use-after-free flaws in Office that could allow unauthorized code execution.

Winsage

January 13, 2026

Microsoft fixes 114 flaws in year’s first Windows 11 Patch Tuesday

Microsoft's January 2026 Patch Tuesday update, KB5074109, addresses 114 vulnerabilities, including a critical zero-day vulnerability (CVE-2026-20805) in the Windows Desktop Window Manager (DWM) that has been actively exploited. The update is applicable to Windows 11 versions 24H2 and 25H2 and includes security enhancements and updates to AI components. Other high-severity vulnerabilities addressed include CVE-2026-20816 (privilege escalation in Windows Installer), CVE-2026-20817 (elevation of privilege in Windows Error Reporting), CVE-2026-20840 (vulnerability in Windows NTFS), CVE-2026-20843 (flaw in Routing and Remote Access Service), CVE-2026-20860 (vulnerability in Ancillary Function Driver for WinSock), and CVE-2026-20871 (another DWM vulnerability). The update removes legacy modem drivers to minimize the attack surface and resolves reliability issues in Azure Virtual Desktop and WSL networking. It also changes the default setting for Windows Deployment Services (WDS) to disable hands-free deployment. Users can install the update through Windows Update, and a system reboot is required for full application.