Microsoft Server Security Advisories & CVEs
1355 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-2026-21508] 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).
Medium [CVE-2026-21222] Windows Kernel Information Disclosure Vulnerability
Insertion of sensitive information into log file in Windows Kernel allows an authorized attacker to disclose information locally. Affected products named by the advisory: Windows Server 2012 R2; Windows Server 2012 R2 (Server Core installation); Windows Server 2016; Windows Server 2016 (Server Core installation); and 6 more. Affected products named by the advisory: Windows Server 2019 (Server Core installation); Windows Server 2022, 23H2 Edition (Server Core installation); Windows Server 2025 (Server Core installation).
Medium [CVE-2026-21525] Windows Remote Access Connection Manager Denial of Service Vulnerability
Null pointer dereference in Windows Remote Access Connection Manager allows an unauthorized attacker to deny service 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).
Medium [CVE-2026-21527] Microsoft Exchange Server Spoofing Vulnerability
User interface (ui) misrepresentation of critical information in Microsoft Exchange Server allows an unauthorized attacker to perform spoofing over a network. Affected products named by the advisory: Microsoft Exchange Server 2016 Cumulative Update 23; Microsoft Exchange Server 2019 Cumulative Update 14; Microsoft Exchange Server 2019 Cumulative Update 15; Microsoft Exchange Server Subscription Edition RTM.
Low [CVE-2026-21249] Windows NTLM Spoofing Vulnerability
External control of file name or path in Windows NTLM allows an unauthorized attacker to perform spoofing locally. Affected products named by the advisory: Windows Server 2012 R2; Windows Server 2012 R2 (Server Core installation); Windows Server 2016; Windows Server 2016 (Server Core installation); and 6 more. Affected products named by the advisory: Windows Server 2019 (Server Core installation); Windows Server 2022, 23H2 Edition (Server Core installation); Windows Server 2025 (Server Core installation).
Critical [CVE-2026-20963] Microsoft SharePoint Remote Code Execution Vulnerability
Deserialization of untrusted data in Microsoft Office SharePoint allows an unauthorized attacker to execute code 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-2026-20941] 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.