Microsoft Server Security Advisories & CVEs
1207 advisories tracked · Microsoft Security Update Guide (MSRC) · direct feeds checked every minute; rate-limited backstops use a safe source cadence
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Official source
Microsoft Security Update Guide (MSRC)
Polled via the official MSRC Security Update Guide RSS feed (api.msrc.microsoft.com, no credentials required), scoped to SERVER products only — Windows Server, Exchange, SQL Server, SharePoint, Hyper-V and companion server roles. Client-only CVEs (Edge, Office apps, consumer Windows) are filtered out via the monthly CVRF document's affected-product list.
Latest MS Server advisories
High [CVE-2026-21253] Mailslot File System Elevation of Privilege Vulnerability
Use after free in Mailslot File System allows an authorized attacker to elevate privileges locally. Affected products named by the advisory: Windows Server 2012; Windows Server 2012 (Server Core installation); Windows Server 2012 R2; Windows Server 2012 R2 (Server Core installation); and 8 more. Affected products named by the advisory: Windows Server 2016 (Server Core installation); Windows Server 2019 (Server Core installation); Windows Server 2022, 23H2 Edition (Server Core installation); Windows Server 2025 (Server Core installation).
High [CVE-2026-21255] Windows Hyper-V Security Feature Bypass Vulnerability
Improper access control in Windows Hyper-V allows an authorized attacker to bypass a security feature locally. Affected products named by the advisory: Windows Server 2016; Windows Server 2016 (Server Core installation); Windows Server 2019; Windows Server 2019 (Server Core installation); and 4 more. Affected products named by the advisory: Windows Server 2022, 23H2 Edition (Server Core installation); Windows Server 2025 (Server Core installation).
High [CVE-2026-21508] Windows Storage Elevation of Privilege Vulnerability
Improper authentication in Windows Storage allows an authorized attacker to elevate privileges locally. Affected products named by the advisory: Windows Server 2012; Windows Server 2012 (Server Core installation); Windows Server 2012 R2; Windows Server 2012 R2 (Server Core installation); and 8 more. Affected products named by the advisory: Windows Server 2016 (Server Core installation); Windows Server 2019 (Server Core installation); Windows Server 2022, 23H2 Edition (Server Core installation); Windows Server 2025 (Server Core installation).
High [CVE-2026-21511] Microsoft Outlook Spoofing Vulnerability
Deserialization of untrusted data in Microsoft Office Outlook allows an unauthorized attacker to perform spoofing over a network. Affected products named by the advisory: Microsoft SharePoint Enterprise Server 2016; Microsoft SharePoint Server 2019; Microsoft SharePoint Server Subscription Edition.
High [CVE-2026-21513] MSHTML Framework Security Feature Bypass Vulnerability
Protection mechanism failure in MSHTML Framework allows an unauthorized attacker to bypass a security feature over a network. Affected products named by the advisory: Windows Server 2012; Windows Server 2012 (Server Core installation); Windows Server 2012 R2; Windows Server 2012 R2 (Server Core installation); and 8 more. Affected products named by the advisory: Windows Server 2016 (Server Core installation); Windows Server 2019 (Server Core installation); Windows Server 2022, 23H2 Edition (Server Core installation); Windows Server 2025 (Server Core installation).
High [CVE-2026-21533] Windows Remote Desktop Services Elevation of Privilege Vulnerability
Improper privilege management in Windows Remote Desktop allows an authorized attacker to elevate privileges locally. Affected products named by the advisory: Windows Server 2012; Windows Server 2012 (Server Core installation); Windows Server 2012 R2; Windows Server 2012 R2 (Server Core installation); and 8 more. Affected products named by the advisory: Windows Server 2016 (Server Core installation); Windows Server 2019 (Server Core installation); Windows Server 2022, 23H2 Edition (Server Core installation); Windows Server 2025 (Server Core installation).
High [CVE-2026-21236] Windows Ancillary Function Driver for WinSock Elevation of Privilege Vulnerability
Heap-based buffer overflow in Windows Ancillary Function Driver for WinSock allows an authorized attacker to elevate privileges locally. Affected products named by the advisory: Windows Server 2012; Windows Server 2012 (Server Core installation); Windows Server 2012 R2; Windows Server 2012 R2 (Server Core installation); and 8 more. Affected products named by the advisory: Windows Server 2016 (Server Core installation); Windows Server 2019 (Server Core installation); Windows Server 2022, 23H2 Edition (Server Core installation); Windows Server 2025 (Server Core installation).
High [CVE-2026-21234] Windows Connected Devices Platform Service Elevation of Privilege Vulnerability
Concurrent execution using shared resource with improper synchronization ('race condition') in Windows Connected Devices Platform Service allows an authorized attacker to elevate privileges locally. Affected products named by the advisory: Windows Server 2019; Windows Server 2019 (Server Core installation); Windows Server 2022; Windows Server 2022, 23H2 Edition (Server Core installation); and 2 more. Affected products named by the advisory: Windows Server 2025 (Server Core installation).
High [CVE-2026-21235] Windows Graphics Component Elevation of Privilege Vulnerability
Use after free in Microsoft Graphics Component allows an authorized attacker to elevate privileges locally. Affected products named by the advisory: Windows Server 2012; Windows Server 2012 (Server Core installation); Windows Server 2012 R2; Windows Server 2012 R2 (Server Core installation); and 5 more. Affected products named by the advisory: Windows Server 2016 (Server Core installation); Windows Server 2019 (Server Core installation); Windows Server 2022.
High [CVE-2026-21242] Windows Subsystem for Linux Elevation of Privilege Vulnerability
Use after free in Windows Subsystem for Linux allows an authorized attacker to elevate privileges locally. Affected products named by the advisory: Windows Server 2022; Windows Server 2022, 23H2 Edition (Server Core installation); Windows Server 2025; Windows Server 2025 (Server Core installation).
High [CVE-2026-21246] Windows Graphics Component Elevation of Privilege Vulnerability
Heap-based buffer overflow in Microsoft Graphics Component allows an authorized attacker to elevate privileges locally. Affected products named by the advisory: Windows Server 2012; Windows Server 2012 (Server Core installation); Windows Server 2012 R2; Windows Server 2012 R2 (Server Core installation); and 8 more. Affected products named by the advisory: Windows Server 2016 (Server Core installation); Windows Server 2019 (Server Core installation); Windows Server 2022, 23H2 Edition (Server Core installation); Windows Server 2025 (Server Core installation).
High [CVE-2026-21260] Microsoft Outlook Spoofing Vulnerability
Exposure of sensitive information to an unauthorized actor in Microsoft Office Outlook allows an unauthorized attacker to perform spoofing over a network. Affected products named by the advisory: Microsoft SharePoint Enterprise Server 2016; Microsoft SharePoint Server 2019; Microsoft SharePoint Server Subscription Edition.
High [CVE-2026-21519] Desktop Window Manager Elevation of Privilege Vulnerability
Access of resource using incompatible type ('type confusion') in Desktop Window Manager allows an authorized attacker to elevate privileges locally. Affected products named by the advisory: Windows Server 2016; Windows Server 2016 (Server Core installation); Windows Server 2019; Windows Server 2019 (Server Core installation); and 4 more. Affected products named by the advisory: Windows Server 2022, 23H2 Edition (Server Core installation); Windows Server 2025 (Server Core installation).
High [CVE-2026-20941] Host Process for Windows Tasks Elevation of Privilege Vulnerability
Improper link resolution before file access ('link following') in Host Process for Windows Tasks allows an authorized attacker to elevate privileges locally. Affected products named by the advisory: Windows Server 2025; Windows Server 2025 (Server Core installation).
High [CVE-2026-20948] Microsoft Word Remote Code Execution Vulnerability
Untrusted pointer dereference in Microsoft Office Word allows an unauthorized attacker to execute code locally. Affected products named by the advisory: Microsoft SharePoint Enterprise Server 2016; Microsoft SharePoint Server 2019.
High [CVE-2026-20931] Windows Telephony Service Elevation of Privilege Vulnerability
External control of file name or path in Windows Telephony Service allows an authorized attacker to elevate privileges over an adjacent network. Affected products named by the advisory: Windows Server 2008 R2 Service Pack 1; Windows Server 2008 R2 Service Pack 1 (Server Core installation); Windows Server 2008 Service Pack 2; Windows Server 2008 Service Pack 2 (Server Core installation); and 12 more. Affected products named by the advisory: Windows Server 2012 (Server Core installation); Windows Server 2012 R2 (Server Core installation); Windows Server 2016 (Server Core installation); Windows Server 2019 (Server Core installation); and 2 more.
High [CVE-2026-20929] Windows HTTP.sys Elevation of Privilege Vulnerability
Improper access control in Windows HTTP.sys allows an authorized attacker to elevate privileges over a network. Affected products named by the advisory: Windows Server 2008 R2 Service Pack 1; Windows Server 2008 R2 Service Pack 1 (Server Core installation); Windows Server 2008 Service Pack 2; Windows Server 2008 Service Pack 2 (Server Core installation); and 10 more. Affected products named by the advisory: Windows Server 2012 (Server Core installation); Windows Server 2012 R2 (Server Core installation); Windows Server 2016 (Server Core installation); Windows Server 2019 (Server Core installation); and 1 more.
High [CVE-2026-20871] Desktop Window Manager Elevation of Privilege Vulnerability
Use after free in Desktop Windows Manager allows an authorized attacker to elevate privileges locally. Affected products named by the advisory: Windows Server 2022; Windows Server 2022, 23H2 Edition (Server Core installation); Windows Server 2025; Windows Server 2025 (Server Core installation).
High [CVE-2026-20870] Windows Win32 Kernel Subsystem Elevation of Privilege Vulnerability
Use after free in Windows Win32K - ICOMP allows an authorized attacker to elevate privileges locally. Affected products named by the advisory: Windows Server 2025; Windows Server 2025 (Server Core installation).
High [CVE-2026-20868] Windows Routing and Remote Access Service (RRAS) Remote Code Execution Vulnerability
Heap-based buffer overflow in Windows Routing and Remote Access Service (RRAS) allows an unauthorized attacker to execute code over a network. Affected products named by the advisory: Windows Server 2008 R2 Service Pack 1; Windows Server 2008 R2 Service Pack 1 (Server Core installation); Windows Server 2008 Service Pack 2; Windows Server 2008 Service Pack 2 (Server Core installation); and 12 more. Affected products named by the advisory: Windows Server 2012 (Server Core installation); Windows Server 2012 R2 (Server Core installation); Windows Server 2016 (Server Core installation); Windows Server 2019 (Server Core installation); and 2 more.