privilege escalation Archives

Winsage

March 18, 2026

Researchers Reveal ‘RegPwn,’ a Windows Registry Vulnerability That Granted SYSTEM Privileges

A Windows vulnerability named "RegPwn" (CVE-2026-24291) allows low-privileged users to elevate their access to full SYSTEM privileges. Discovered by the MDSec red team, it has been in use since January 2025 and was addressed in a recent Microsoft Patch Tuesday update. The vulnerability exploits the management of Windows accessibility features, which generate a registry key that grants full control to low-privileged users. When a user activates an accessibility tool, the configurations are copied into the local machine registry hive, which remains writable by the logged-in user. This creates an opportunity for manipulation, especially when user-controlled settings interact with the Windows Secure Desktop environment. An attacker can exploit this by modifying their user-level accessibility registry key and using an oplock on a system file, allowing them to replace the local machine registry key with a symbolic link to an arbitrary system registry key. This process operates under SYSTEM privileges, enabling the attacker to write arbitrary values to restricted areas of the Windows registry. MDSec demonstrated this technique to gain access to a SYSTEM-level command prompt. Microsoft has released security updates to address this vulnerability, and MDSec has made the exploit code available on GitHub for research purposes.

Winsage

March 11, 2026

Microsoft Patch Tuesday, March 2026 Edition

Microsoft Corp. has released security updates addressing at least 77 vulnerabilities across its Windows operating systems and various software applications. Key vulnerabilities include: - CVE-2026-21262: Allows an attacker to elevate privileges on SQL Server 2016 and later, with a CVSS v3 base score of 8.8. - CVE-2026-26127: Affects applications running on .NET, potentially leading to denial of service. - CVE-2026-26113 and CVE-2026-26110: Remote code execution flaws in Microsoft Office exploitable by viewing malicious messages in the Preview Pane. - CVE-2026-24291, CVE-2026-24294, CVE-2026-24289, and CVE-2026-25187: Privilege escalation vulnerabilities rated CVSS 7.8. - CVE-2026-21536: A critical remote code execution bug identified by an AI agent, marking a shift toward AI-driven vulnerability discovery. Additionally, Microsoft previously addressed nine browser vulnerabilities and issued an out-of-band update on March 2 for Windows Server 2022. Adobe has released updates for 80 vulnerabilities across its products, and Mozilla Firefox version 148.0.2 has resolved three high-severity CVEs.

Winsage

March 4, 2026

PoC Exploit Released for Microsoft Windows Error Reporting ALPC Privilege Escalation

A proof-of-concept exploit for CVE-2026-20817, a local privilege escalation vulnerability in the Windows Error Reporting (WER) service, has been released by security researcher oxfemale on GitHub. This vulnerability allows low-privileged users to gain SYSTEM-level access through crafted Advanced Local Procedure Call (ALPC) messages. The flaw is located in the WER service's SvcElevatedLaunch method, which fails to validate caller privileges before executing WerFault.exe with user-supplied command line parameters. The CVSS v3.1 base score for this vulnerability is 7.8, indicating a high severity level. It affects unpatched versions of Windows 10, Windows 11, Windows Server 2019, and Windows Server 2022 prior to the January 2026 update. Demonstrations have shown successful exploitation on Windows 11 23H2. Security teams are advised to monitor for unusual processes related to WerFault.exe, investigate missing SeTcbPrivilege in SYSTEM tokens, and review WER-related activities from low-privilege users. Immediate application of the January 2026 security patches is recommended, and a temporary workaround involves disabling the WER service.

Winsage

March 3, 2026

PoC Exploit Released for Windows Error Reporting ALPC Privilege Escalation

A critical local privilege escalation vulnerability, tracked as CVE-2026-20817, affects Microsoft Windows through the Windows Error Reporting (WER) service. This flaw allows authenticated users with low-level privileges to execute arbitrary code with full SYSTEM privileges. The vulnerability resides in the SvcElevatedLaunch method (0x0D) and fails to validate user permissions, enabling attackers to launch WerFault.exe with malicious command-line parameters from a shared memory block. The exploit affects all versions of Windows 10 and Windows 11 prior to January 2026, as well as Windows Server 2019 and 2022. Microsoft addressed this vulnerability in the January 2026 Security Update. Organizations are advised to apply security patches and monitor for unusual WerFault.exe processes.

Winsage

February 26, 2026

PoC Published for Microsoft Windows Flaw That Allows Low-Privileged Users to Force Irrecoverable BSODs

Security researchers have developed a working Proof of Concept (PoC) exploit for a vulnerability in the Windows kernel, identified as CVE-2026-2636, which allows low-privileged users to induce a Blue Screen of Death (BSoD), resulting in a Denial of Service. This vulnerability is linked to the Windows Common Log File System (CLFS) driver, specifically the CLFS.sys component, and arises from improper handling of invalid or special elements within CLFS (CWE-159). The PoC demonstrates that a non-administrative user can trigger the bug by executing a crafted ReadFile operation on a handle linked to an opened .blf log file without the expected I/O Request Packet (IRP) flags set. This leads to a critical inconsistency in the driver, causing Windows to invoke the kernel routine KeBugCheckEx, which results in a BSoD. The CVE-2026-2636 has a CVSS score of 5.5 (Medium) and poses a high impact on availability, allowing any authenticated user to crash the host reliably. Microsoft addressed this vulnerability in the September 2025 cumulative update, protecting systems running Windows 11 2024 LTSC and Windows Server 2025 by default. However, older or unpatched builds remain vulnerable. Organizations are advised to verify the deployment of the September 2025 updates, prioritize patching multi-user systems, and monitor for unusual spikes in BSoD events.

Winsage

February 12, 2026

Microsoft’s latest update patches six zero-days and two critical flaws – but is it another buggy mess?

Microsoft's February Patch Tuesday update addresses feature and security bugs, continuing the refresh of Secure Boot certificates to protect against bootkit malware. Secure Boot prevents malicious software from executing during startup by using trusted certificates, many of which are set to expire in June. The update is available for both Windows 11 and Windows 10 users, with the latter needing to be enrolled in the Extended Security Updates (ESU) program until October 2026. Windows 11 fixes include resolutions for full-screen gaming and WPA3-Personal Wi-Fi connectivity issues, while Windows 10 improvements address Chinese fonts, specific graphics processing units, and custom folder names in File Explorer. A bug causing unexpected restarts in Secure Launch-compatible PCs has also been fixed. The update includes 55 security patches, a decrease from January's 114, with two classified as critical and six identified as zero-day vulnerabilities. One vulnerability exploited in the wild could allow system privilege escalation, another could disrupt network connectivity, and a third could disable security controls and access sensitive data. Users can update their Windows 11 PCs through System > Windows Update, and Windows 10 users through System > Update & Security. Due to previous buggy updates, users may consider waiting a few days before installing the February update, with the option to uninstall if issues arise.

Winsage

February 12, 2026

February 2026 Patch Tuesday includes six actively exploited zero-days

Microsoft released security updates on the second Tuesday of each month, addressing 59 vulnerabilities this month, including six critical zero-day exploits. 1. CVE-2026-21510: Windows Shell security feature bypass vulnerability (CVSS score 8.8) allows attackers to circumvent Windows SmartScreen by tricking users into opening malicious links or shortcuts. 2. CVE-2026-21513: MSHTML Framework security feature bypass vulnerability (CVSS score 8.8) enables attackers to weaken browser protections by persuading users to open malicious HTML files or shortcuts. 3. CVE-2026-21514: Microsoft Word security feature bypass vulnerability (CVSS score 5.5) allows attackers to exploit untrusted inputs in malicious Word documents to execute blocked content. 4. CVE-2026-21519: Desktop Window Manager elevation of privilege vulnerability (CVSS score 7.8) allows low-privileged attackers to gain higher privileges without user interaction. 5. CVE-2026-21525: Windows Remote Access Connection Manager denial-of-service vulnerability (CVSS score 6.2) can be exploited by unauthenticated local attackers to crash the service without compromising confidentiality or integrity. 6. CVE-2026-21533: Windows Remote Desktop Services elevation of privilege vulnerability (CVSS score 7.8) allows local authenticated attackers to escalate privileges to SYSTEM without user interaction. Additionally, Azure users should be aware of two critical vulnerabilities with CVSS ratings of 9.8.

Winsage

February 11, 2026

Microsoft fixes six actively exploited flaws in latest Windows 11 update

Microsoft's February 2026 Patch Tuesday addressed 59 vulnerabilities in Windows 11, with six confirmed as actively exploited. The most critical vulnerability is CVE-2026-21510, a Windows Shell security feature bypass with a CVSS rating of 8.8, allowing attackers to evade warnings by tricking users into opening malicious files. Another significant vulnerability, CVE-2026-21513, also rated at 8.8, affects MSHTML and allows remote attackers to bypass execution prompts through malicious code in HTML or shortcut files. CVE-2026-21514 impacts Microsoft Word and enables adversaries to disable OLE mitigations, posing risks through document-based attacks. Two local privilege escalation vulnerabilities are CVE-2026-21519 in Desktop Window Manager and CVE-2026-21533 in Windows Remote Desktop Services, with CVSS scores of 7.8. CVE-2026-21525 is a denial-of-service vulnerability in Remote Access Connection Manager. The update includes 53 additional vulnerabilities across various Microsoft products and services, with CVE-2026-21531 in Azure SDK rated at 9.8 and CVE-2026-20841 affecting Windows Notepad rated at 8.8. The cumulative update for Windows 11 (KB5077181) also includes enhancements and resolves WPA3 Wi-Fi connectivity issues. Microsoft reminded users of the June 2026 expiration of Secure Boot certificates, which requires timely updates to ensure secure booting. Users can install the updates via Windows Update.

Winsage

January 30, 2026

Microsoft to disable NTLM by default in future Windows releases

Microsoft will disable the NTLM authentication protocol by default in the next major Windows Server release and associated Windows client versions. NTLM, introduced in 1993, has been vulnerable to various cyberattacks, including NTLM relay and pass-the-hash attacks. The transition plan includes three phases: enhanced auditing tools in Windows 11 24H2 and Windows Server 2025, new features like IAKerb and a Local Key Distribution Center in late 2026, and eventually disabling network NTLM by default in future releases. NTLM will remain in the operating system but will not be used automatically. Microsoft deprecated NTLM authentication in July 2024 and has encouraged developers to transition to Kerberos or Negotiation authentication.

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.