As 2026 gets underway, the pace of critical vulnerability disclosures shows little sign of easing. Following the recent MongoBleed (CVE-2025-14847) revelation, Microsoft has kicked off the year with its first Patch Tuesday release, addressing 114 security flaws across its product ecosystem. Among them is a zero-day vulnerability that was already being exploited in real-world attacks, underscoring the persistent pressure on defenders to keep pace.
The actively exploited flaw, tracked as CVE-2026-20805, has been classified by Microsoft as an important-severity information disclosure vulnerability affecting the Windows Desktop Window Manager (DWM). The issue allows a locally authorized attacker to access sensitive information by abusing weaknesses in how DWM handles system data, potentially exposing details that should otherwise remain protected.
Given Microsoft’s dominant role in powering enterprise and consumer environments worldwide, vulnerabilities in its software carry far-reaching implications. The 2025 BeyondTrust Microsoft Vulnerabilities Report revealed that 2024 set a new record with 1,360 disclosed Microsoft vulnerabilities—an 11% increase year over year—driven largely by Elevation of Privilege (EoP) and RCE flaws. That momentum continued into 2025, with Microsoft patching 1,129 CVEs, marking the second consecutive year the company surpassed the 1,000-vulnerability threshold. Notably, December 2025’s Patch Tuesday was dominated by EoP issues, which accounted for half of all fixes, followed by RCE vulnerabilities at nearly one-third.
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CVE-2026-20805 Analysis
Microsoft’s January 2026 Patch Tuesday release delivers fixes for 112 security vulnerabilities spanning a wide range of products, including Windows, Office, Azure, Edge, SharePoint, SQL Server, SMB, and Windows management services. When third-party Chromium-related patches are included, the total number of addressed flaws increases to 114, with 106 classified as Important in severity.
One of the central issues within this release is a zero-day vulnerability that was already being exploited in the wild. Identified as CVE-2026-20805, the flaw affects the Windows Desktop Window Manager and allows for unintended disclosure of sensitive information.
According to Microsoft, the vulnerability enables a locally authenticated attacker to extract protected data by abusing the way Desktop Window Manager handles memory. Specifically, successful exploitation could expose a section address from a remote ALPC port residing in user-mode memory, potentially providing attackers with insight useful for further compromise.
Microsoft credits its internal security teams with discovering CVE-2026-20805, though the company has not released technical details regarding the active exploitation observed prior to patching.
In response to confirmed exploitation, the U.S. Cybersecurity and Infrastructure Security Agency (CISA) has added CVE-2026-20805 to its Known Exploited Vulnerabilities (KEV) catalog. Federal Civilian Executive Branch (FCEB) agencies are now required to apply the corresponding updates no later than February 3, 2026, highlighting the urgency of remediation.
Organizations that rely on corresponding Windows products are urged to apply the patches immediately. Also, by enhancing the defenses with SOC Prime’s AI-Native Detection Intelligence Platform, SOC teams can source detection content from the largest and up-to-date repository, seamlessly adopt the full pipeline from detection to simulation into their security processes, orchestrate workflows in their natural language, and smoothly navigate the ever-changing threat landscape while strengthening defenses at scale.
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