Microsoft Windows 11 26H1 vulnerabilities

CVE-2026-40405 [HIGH] CWE-476 CVE-2026-40405: Null pointer dereference in Windows TCP/IP allows an unauthorized attacker to deny service over a ne Null pointer dereference in Windows TCP/IP allows an unauthorized attacker to deny service over a network.

CVE-2026-42837 [HIGH] CWE-125 CVE-2026-42837: Out-of-bounds read in Windows Projected File System Filter Driver allows an authorized attacker to e Out-of-bounds read in Windows Projected File System Filter Driver allows an authorized attacker to elevate privileges locally.

CVE-2026-42828 [HIGH] CWE-126 CVE-2026-42828: Buffer over-read in Windows Projected File System Filter Driver allows an authorized attacker to ele Buffer over-read in Windows Projected File System Filter Driver allows an authorized attacker to elevate privileges locally.

CVE-2026-50647 [HIGH] CWE-835 CVE-2026-50647: Loop with unreachable exit condition ('infinite loop') in Active Directory Federation Services (AD F Loop with unreachable exit condition ('infinite loop') in Active Directory Federation Services (AD FS) allows an unauthorized attacker to deny service over a network.

CVE-2026-50422 [HIGH] CWE-125 CVE-2026-50422: Out-of-bounds read in Windows NTFS allows an authorized attacker to elevate privileges locally. Out-of-bounds read in Windows NTFS allows an authorized attacker to elevate privileges locally.

CVE-2026-50315 [HIGH] CWE-476 CVE-2026-50315: Null pointer dereference in Windows Image Acquisition allows an authorized attacker to elevate privi Null pointer dereference in Windows Image Acquisition allows an authorized attacker to elevate privileges locally.

CVE-2026-50357 [HIGH] CWE-197 CVE-2026-50357: Numeric truncation error in Windows Resilient File System (ReFS) allows an authorized attacker to ex Numeric truncation error in Windows Resilient File System (ReFS) allows an authorized attacker to execute code locally.

CVE-2026-54115 [HIGH] CWE-122 CVE-2026-54115: Integer overflow or wraparound in Windows Active Directory allows an authorized attacker to elevate Integer overflow or wraparound in Windows Active Directory allows an authorized attacker to elevate privileges locally.

CVE-2026-40409 [HIGH] CWE-197 CVE-2026-40409: Windows Universal Disk Format File System Driver (UDFS) Elevation of Privilege Vulnerability Windows Universal Disk Format File System Driver (UDFS) Elevation of Privilege Vulnerability

CVE-2026-27907 [HIGH] CWE-191 CVE-2026-27907: Integer underflow (wrap or wraparound) in Windows Storage Spaces Controller allows an authorized att Integer underflow (wrap or wraparound) in Windows Storage Spaces Controller allows an authorized attacker to elevate privileges locally.

CVE-2026-45592 [HIGH] CWE-190 CVE-2026-45592: Integer overflow or wraparound in Windows Internet (wininet.dll) allows an authorized attacker to el Integer overflow or wraparound in Windows Internet (wininet.dll) allows an authorized attacker to elevate privileges locally.

CVE-2026-26153 [HIGH] CWE-125 CVE-2026-26153: Out-of-bounds read in Windows Encrypting File System (EFS) allows an authorized attacker to elevate Out-of-bounds read in Windows Encrypting File System (EFS) allows an authorized attacker to elevate privileges locally.

CVE-2026-42896 [HIGH] CWE-122 CVE-2026-42896: Integer overflow or wraparound in Windows DWM Core Library allows an authorized attacker to elevate Integer overflow or wraparound in Windows DWM Core Library allows an authorized attacker to elevate privileges locally.

CVE-2026-50335 [HIGH] CWE-284 CVE-2026-50335: Improper access control in Windows Operating Systems allows an authorized attacker to elevate privil Improper access control in Windows Operating Systems allows an authorized attacker to elevate privileges locally.

CVE-2026-50346 [HIGH] CWE-285 CVE-2026-50346: Improper authorization in RPC Runtime allows an authorized attacker to elevate privileges locally. Improper authorization in RPC Runtime allows an authorized attacker to elevate privileges locally.

CVE-2026-33834 [HIGH] CWE-284 CVE-2026-33834: Improper access control in Windows Event Logging Service allows an authorized attacker to elevate pr Improper access control in Windows Event Logging Service allows an authorized attacker to elevate privileges locally.

CVE-2026-50491 [HIGH] CWE-125 CVE-2026-50491: Out-of-bounds read in Code Integrity DLL (ci.dll) allows an authorized attacker to elevate privilege Out-of-bounds read in Code Integrity DLL (ci.dll) allows an authorized attacker to elevate privileges locally.

CVE-2026-49792 [HIGH] CWE-197 CVE-2026-49792: Numeric truncation error in Windows Resilient File System (ReFS) allows an authorized attacker to ex Numeric truncation error in Windows Resilient File System (ReFS) allows an authorized attacker to execute code locally.

CVE-2026-49783 [HIGH] CWE-358 CVE-2026-49783: Improperly implemented security check for standard in Windows Secure Boot allows an authorized attac Improperly implemented security check for standard in Windows Secure Boot allows an authorized attacker to bypass a security feature locally.

CVE-2026-34338 [HIGH] CWE-416 CVE-2026-34338: Use after free in Windows Telephony Service allows an authorized attacker to elevate privileges loca Use after free in Windows Telephony Service allows an authorized attacker to elevate privileges locally.