CVE-2026-56176ImportantRevised 17 Sep
Windows Win32k Elevation of Privilege Vulnerability
Assessment
Out-of-bounds read in Windows Win32K - GRFX allows an authorized attacker to elevate privileges locally.
- Severity
- Important
- CVSS base score
- 7.8CVSS:3.1/
AV:L/ AC:L/ PR:L/ UI:N/ S:U/ C:H/ I:H/ A:H/ E:U/ RL:O/ RC:C - Impact
- Elevation of Privilege
- EPSS, next 30 days
- 0.3%Higher than 24% of scored CVEs · FIRST model run 26 Sep 2026 · about EPSS
- Exploitability
- Exploitation Less Likely
- Publicly disclosed
- No
- Customer action
- Required: apply the update
- Component
- Windows Win32K - GRFX
- Weakness
- CWE-125: Out-of-bounds Read
- Issued by
- Microsoft
- Published
- 14 Jul 2026 · July 2026
- Last revised
- 17 Sep 2026Added Office software to the Security Updates table. Customers that are running supported version of Office are encouraged to update to the indicated version to be protected from this vulnerability.
Updates that fix it
9 KBs| KB | Type | Restart | Applies to | Other CVEs |
|---|---|---|---|---|
| KB5099444 | Monthly Rollup | Required | Windows Server 2012 R2, Windows Server 2012 R2 (Server Core installation) | All CVEs in KB5099444 |
| KB5099445 | Monthly Rollup | Required | Windows Server 2012, Windows Server 2012 (Server Core installation) | All CVEs in KB5099445 |
| KB5099535 | Security Update | Required | Windows 10 Version 1607 for 32-bit Systems, Windows 10 Version 1607 for x64-based Systems, Windows Server 2016 and 1 more | All CVEs in KB5099535 |
| KB5099536 | Security Update | Required | Windows Server 2025, Windows Server 2025 (Server Core installation) | All CVEs in KB5099536 |
| KB5099538 | Security Update | Required | Windows 10 Version 1809 for 32-bit Systems, Windows 10 Version 1809 for x64-based Systems, Windows Server 2019 and 1 more | All CVEs in KB5099538 |
| KB5099539 | Security Update | Required | Windows 10 Version 21H2 for 32-bit Systems, Windows 10 Version 21H2 for ARM64-based Systems, Windows 10 Version 21H2 for x64-based Systems and 3 more | All CVEs in KB5099539 |
| KB5099540 | Security Update | Required | Windows Server 2022 | All CVEs in KB5099540 |
| KB5101649 | Security Update | Required | Windows 11 Version 26H1 for ARM64-based Systems, Windows 11 version 26H1 for x64-based Systems | All CVEs in KB5101649 |
| KB5101650 | Security Update | Required | Windows 11 Version 24H2 for ARM64-based Systems, Windows 11 Version 24H2 for x64-based Systems, Windows 11 Version 25H2 for ARM64-based Systems and 1 more | All CVEs in KB5101650 |
Affected products
ESU, Microsoft Office, Windows31 affected products
- Microsoft Office 365 for Mac
- Microsoft Office for Android
- Microsoft Office LTSC for Mac 2021
- Microsoft Office LTSC for Mac 2024
- Windows 10 Version 1607 for 32-bit Systems
- Windows 10 Version 1607 for x64-based Systems
- Windows 10 Version 1809 for 32-bit Systems
- Windows 10 Version 1809 for x64-based Systems
- Windows 10 Version 21H2 for 32-bit Systems
- Windows 10 Version 21H2 for ARM64-based Systems
- Windows 10 Version 21H2 for x64-based Systems
- Windows 10 Version 22H2 for 32-bit Systems
- Windows 10 Version 22H2 for ARM64-based Systems
- Windows 10 Version 22H2 for x64-based Systems
- Windows 11 Version 24H2 for ARM64-based Systems
- Windows 11 Version 24H2 for x64-based Systems
- Windows 11 Version 25H2 for ARM64-based Systems
- Windows 11 Version 25H2 for x64-based Systems
- Windows 11 Version 26H1 for ARM64-based Systems
- Windows 11 version 26H1 for x64-based Systems
- Windows Server 2012
- Windows Server 2012 (Server Core installation)
- Windows Server 2012 R2
- Windows Server 2012 R2 (Server Core installation)
- Windows Server 2016
- Windows Server 2016 (Server Core installation)
- Windows Server 2019
- Windows Server 2019 (Server Core installation)
- Windows Server 2022
- Windows Server 2025
- Windows Server 2025 (Server Core installation)