Microsoft Windows 11 Version 26H1 vulnerabilities

CVE-2026-21236 [HIGH] CWE-122 CVE-2026-21236: Heap-based buffer overflow in Windows Ancillary Function Driver for WinSock allows an authorized att Heap-based buffer overflow in Windows Ancillary Function Driver for WinSock allows an authorized attacker to elevate privileges locally.

CVE-2026-50501 [HIGH] CWE-121 CVE-2026-50501: Stack-based buffer overflow in Windows Resilient File System (ReFS) allows an unauthorized attacker Stack-based buffer overflow in Windows Resilient File System (ReFS) allows an unauthorized attacker to execute code locally.

CVE-2026-50407 [HIGH] CWE-122 CVE-2026-50407: Heap-based buffer overflow in Windows Resilient File System (ReFS) allows an authorized attacker to Heap-based buffer overflow in Windows Resilient File System (ReFS) allows an authorized attacker to elevate privileges locally.

CVE-2026-45638 [HIGH] CWE-122 CVE-2026-45638: Heap-based buffer overflow in Windows Ancillary Function Driver for WinSock allows an authorized att Heap-based buffer overflow in Windows Ancillary Function Driver for WinSock allows an authorized attacker to elevate privileges locally.

CVE-2026-49184 [HIGH] CWE-122 CVE-2026-49184: Heap-based buffer overflow in Windows NTFS allows an unauthorized attacker to execute code locally. Heap-based buffer overflow in Windows NTFS allows an unauthorized attacker to execute code locally.

CVE-2026-50482 [HIGH] CWE-122 CVE-2026-50482: 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-2026-58640 [HIGH] CWE-122 CVE-2026-58640: 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-2026-49175 [HIGH] CWE-122 CVE-2026-49175: Heap-based buffer overflow in Windows DNS allows an authorized attacker to elevate privileges locall Heap-based buffer overflow in Windows DNS allows an authorized attacker to elevate privileges locally.

CVE-2026-50309 [HIGH] CWE-122 CVE-2026-50309: 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-2026-54987 [HIGH] CWE-122 CVE-2026-54987: Heap-based buffer overflow in Windows Overlay Filter allows an authorized attacker to elevate privil Heap-based buffer overflow in Windows Overlay Filter allows an authorized attacker to elevate privileges locally.

CVE-2026-40406 [HIGH] CWE-416 CVE-2026-40406: Use after free in Windows TCP/IP allows an unauthorized attacker to disclose information over a netw Use after free in Windows TCP/IP allows an unauthorized attacker to disclose information over a network.

CVE-2026-48563 [HIGH] CWE-416 CVE-2026-48563: Use after free in Remote Desktop Client allows an unauthorized attacker to execute code over a netwo Use after free in Remote Desktop Client allows an unauthorized attacker to execute code over a network.

CVE-2026-56648 [HIGH] CWE-367 CVE-2026-56648: Time-of-check time-of-use (toctou) race condition in Windows Network File System allows an authorize Time-of-check time-of-use (toctou) race condition in Windows Network File System allows an authorized attacker to elevate privileges over a network.

CVE-2026-42913 [HIGH] CWE-362 CVE-2026-42913: Concurrent execution using shared resource with improper synchronization ('race condition') in Remot Concurrent execution using shared resource with improper synchronization ('race condition') in Remote Desktop Client allows an unauthorized attacker to execute code over a network.

CVE-2026-44801 [HIGH] CWE-416 CVE-2026-44801: Use after free in Remote Desktop Client allows an unauthorized attacker to execute code over a netwo Use after free in Remote Desktop Client allows an unauthorized attacker to execute code over a network.

CVE-2026-42909 [HIGH] CWE-362 CVE-2026-42909: Concurrent execution using shared resource with improper synchronization ('race condition') in Remot Concurrent execution using shared resource with improper synchronization ('race condition') in Remote Desktop Client allows an unauthorized attacker to execute code over a network.

CVE-2026-54128 [HIGH] CWE-416 CVE-2026-54128: Use after free in Windows DHCP Client allows an unauthorized attacker to execute code locally. Use after free in Windows DHCP Client allows an unauthorized attacker to execute code locally.

CVE-2026-27909 [HIGH] CWE-416 CVE-2026-27909: Use after free in Microsoft Windows Search Component allows an authorized attacker to elevate privil Use after free in Microsoft Windows Search Component allows an authorized attacker to elevate privileges locally.

CVE-2026-54127 [HIGH] CWE-416 CVE-2026-54127: Use after free in Windows Hyper-V allows an unauthorized attacker to elevate privileges locally. Use after free in Windows Hyper-V allows an unauthorized attacker to elevate privileges locally.

CVE-2026-40400 [HIGH] CWE-23 CVE-2026-40400: Relative path traversal in Windows PowerShell allows an authorized attacker to execute code over a n Relative path traversal in Windows PowerShell allows an authorized attacker to execute code over a network.