Microsoft Windows 10 21H2 vulnerabilities

CVE-2026-20877 [HIGH] CWE-362 CVE-2026-20877: Use after free in Windows Management Services allows an authorized attacker to elevate privileges lo Use after free in Windows Management Services allows an authorized attacker to elevate privileges locally.

CVE-2026-20817 [HIGH] CWE-280 CVE-2026-20817: Improper handling of insufficient permissions or privileges in Windows Error Reporting allows an aut Improper handling of insufficient permissions or privileges in Windows Error Reporting allows an authorized attacker to elevate privileges locally.

CVE-2026-20832 [HIGH] CWE-415 CVE-2026-20832: Windows Remote Procedure Call Interface Definition Language (IDL) Elevation of Privilege Vulnerabili Windows Remote Procedure Call Interface Definition Language (IDL) Elevation of Privilege Vulnerability

CVE-2026-20843 [HIGH] CWE-284 CVE-2026-20843: Improper access control in Windows Routing and Remote Access Service (RRAS) allows an authorized att Improper access control in Windows Routing and Remote Access Service (RRAS) allows an authorized attacker to elevate privileges locally.

CVE-2026-20860 [HIGH] CWE-843 CVE-2026-20860: Access of resource using incompatible type ('type confusion') in Windows Ancillary Function Driver f Access of resource using incompatible type ('type confusion') in Windows Ancillary Function Driver for WinSock allows an authorized attacker to elevate privileges locally.

CVE-2026-20926 [HIGH] CWE-362 CVE-2026-20926: Concurrent execution using shared resource with improper synchronization ('race condition') in Windo Concurrent execution using shared resource with improper synchronization ('race condition') in Windows SMB Server allows an authorized attacker to elevate privileges over a network.

CVE-2026-20816 [HIGH] CWE-367 CVE-2026-20816: Time-of-check time-of-use (toctou) race condition in Windows Installer allows an authorized attacker Time-of-check time-of-use (toctou) race condition in Windows Installer allows an authorized attacker to elevate privileges locally.

CVE-2026-20857 [HIGH] CWE-822 CVE-2026-20857: Untrusted pointer dereference in Windows Cloud Files Mini Filter Driver allows an authorized attacke Untrusted pointer dereference in Windows Cloud Files Mini Filter Driver allows an authorized attacker to elevate privileges locally.

CVE-2026-20921 [HIGH] CWE-362 CVE-2026-20921: Concurrent execution using shared resource with improper synchronization ('race condition') in Windo Concurrent execution using shared resource with improper synchronization ('race condition') in Windows SMB Server allows an authorized attacker to elevate privileges over a network.

CVE-2026-20822 [HIGH] CWE-416 CVE-2026-20822: Use after free in Microsoft Graphics Component allows an authorized attacker to elevate privileges l Use after free in Microsoft Graphics Component allows an authorized attacker to elevate privileges locally.

CVE-2026-20856 [HIGH] CWE-20 CVE-2026-20856: Improper input validation in Windows Server Update Service allows an unauthorized attacker to execut Improper input validation in Windows Server Update Service allows an unauthorized attacker to execute code over a network.

CVE-2026-20922 [HIGH] CWE-122 CVE-2026-20922: Heap-based buffer overflow in Windows NTFS allows an authorized attacker to execute code locally. Heap-based buffer overflow in Windows NTFS allows an authorized attacker to execute code locally.

CVE-2026-20831 [HIGH] CWE-367 CVE-2026-20831: Time-of-check time-of-use (toctou) race condition in Windows Ancillary Function Driver for WinSock a Time-of-check time-of-use (toctou) race condition in Windows Ancillary Function Driver for WinSock allows an authorized attacker to elevate privileges locally.

CVE-2026-20919 [HIGH] CWE-362 CVE-2026-20919: Concurrent execution using shared resource with improper synchronization ('race condition') in Windo Concurrent execution using shared resource with improper synchronization ('race condition') in Windows SMB Server allows an authorized attacker to elevate privileges over a network.

CVE-2026-20931 [HIGH] CWE-73 CVE-2026-20931: External control of file name or path in Windows Telephony Service allows an authorized attacker to External control of file name or path in Windows Telephony Service allows an authorized attacker to elevate privileges over an adjacent network.

CVE-2026-20814 [HIGH] CWE-362 CVE-2026-20814: Concurrent execution using shared resource with improper synchronization ('race condition') in Graph Concurrent execution using shared resource with improper synchronization ('race condition') in Graphics Kernel allows an authorized attacker to elevate privileges locally.

CVE-2026-20826 [HIGH] CWE-362 CVE-2026-20826: Concurrent execution using shared resource with improper synchronization ('race condition') in Table Concurrent execution using shared resource with improper synchronization ('race condition') in Tablet Windows User Interface (TWINUI) Subsystem allows an authorized attacker to elevate privileges locally.

CVE-2026-20810 [HIGH] CWE-590 CVE-2026-20810: Free of memory not on the heap in Windows Ancillary Function Driver for WinSock allows an authorized Free of memory not on the heap in Windows Ancillary Function Driver for WinSock allows an authorized attacker to elevate privileges locally.

CVE-2026-20924 [HIGH] CWE-362 CVE-2026-20924: Use after free in Windows Management Services allows an authorized attacker to elevate privileges lo Use after free in Windows Management Services allows an authorized attacker to elevate privileges locally.

CVE-2026-20809 [HIGH] CWE-122 CVE-2026-20809: Time-of-check time-of-use (toctou) race condition in Windows Kernel Memory allows an authorized atta Time-of-check time-of-use (toctou) race condition in Windows Kernel Memory allows an authorized attacker to elevate privileges locally.