Read the docs
TI-2026-72640 Aliases CVE-2026-83903GHSA-9268-6277-cgg6

Heap overflow in Windows Direct Composition enables privilege gain

Priority LOW 36CWE-122Published · Updated

Key facts

Attack vector
Local
Privileges required
Low
User interaction
None
Attack complexity
Low
Impact type
Code execution
Confidentiality · integrity · availability
High · High · High
Fix status
Fixed

Attack profile from CVSS 3.1 · CNA. Fix status from CNA. Impact type from CWE-122 and the CVSS impact.

Summary

Microsoft Windows 11 versions 24H2, 25H2 and 26H2 and Windows Server 2025 (including Server Core installations) are affected. A heap-based buffer overflow (CWE-122) in Windows Direct Composition lets an authorized local attacker with low privileges gain higher privileges.

Written with Claude Haiku 5.5 from the sources below · 2026-10-28

Description from the CNA

Heap-based buffer overflow in Windows Direct Composition allows an authorized attacker to elevate privileges locally.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00379 32nd percentileScored 2026-11-07
Fix Fixed Windows 11 Version 24H2 (Microsoft): 10.0.26100.9711Windows 11 Version 25H2 (Microsoft): 10.0.26200.9711+3 more products

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
None
Automatable
No
Technical impact
Total

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
MicrosoftWindows 11 Version 24H210.0.26100.0 to before 10.0.26100.971110.0.26100.9711Patch availableCNA
MicrosoftWindows 11 Version 25H210.0.26200.0 to before 10.0.26200.971110.0.26200.9711Patch availableCNA
MicrosoftWindows 11 Version 26H210.0.26300.0 to before 10.0.26300.971110.0.26300.9711Patch availableCNA
MicrosoftWindows Server 202510.0.26100.0 to before 10.0.26100.3365010.0.26100.33650Patch availableCNA
MicrosoftWindows Server 2025 (Server Core installation)10.0.26100.0 to before 10.0.26100.3365010.0.26100.33650Patch availableCNA
  • Windows 11 Version 24H2 VendorMicrosoft Affected 10.0.26100.0 to before 10.0.26100.9711 Fixed in 10.0.26100.9711 Patch available CNA
  • Windows 11 Version 25H2 VendorMicrosoft Affected 10.0.26200.0 to before 10.0.26200.9711 Fixed in 10.0.26200.9711 Patch available CNA
  • Windows 11 Version 26H2 VendorMicrosoft Affected 10.0.26300.0 to before 10.0.26300.9711 Fixed in 10.0.26300.9711 Patch available CNA
  • Windows Server 2025 VendorMicrosoft Affected 10.0.26100.0 to before 10.0.26100.33650 Fixed in 10.0.26100.33650 Patch available CNA
  • Windows Server 2025 (Server Core installation) VendorMicrosoft Affected 10.0.26100.0 to before 10.0.26100.33650 Fixed in 10.0.26100.33650 Patch available CNA

CPE configurations NVD · 7

CPEVersionsRoleVendor
cpe:2.3:o:microsoft:windows_11_24h2:*:*:*:*:*:*:arm64:*before 10.0.26100.9711VulnerableMicrosoft
cpe:2.3:o:microsoft:windows_11_24h2:*:*:*:*:*:*:x64:*before 10.0.26100.9711VulnerableMicrosoft
cpe:2.3:o:microsoft:windows_11_25h2:*:*:*:*:*:*:arm64:*before 10.0.26200.9711VulnerableMicrosoft
cpe:2.3:o:microsoft:windows_11_25h2:*:*:*:*:*:*:x64:*before 10.0.26200.9711VulnerableMicrosoft
cpe:2.3:o:microsoft:windows_11_26h2:*:*:*:*:*:*:arm64:*before 10.0.26300.9711VulnerableMicrosoft
cpe:2.3:o:microsoft:windows_11_26h2:*:*:*:*:*:*:x64:*before 10.0.26300.9711VulnerableMicrosoft
cpe:2.3:o:microsoft:windows_server_2025:*:*:*:*:*:*:x64:*before 10.0.26100.33650VulnerableMicrosoft
  • cpe:2.3:o:microsoft:windows_11_24h2:*:*:*:*:*:*:arm64:* Versions before 10.0.26100.9711 Vulnerable ·Microsoft
  • cpe:2.3:o:microsoft:windows_11_24h2:*:*:*:*:*:*:x64:* Versions before 10.0.26100.9711 Vulnerable ·Microsoft
  • cpe:2.3:o:microsoft:windows_11_25h2:*:*:*:*:*:*:arm64:* Versions before 10.0.26200.9711 Vulnerable ·Microsoft
  • cpe:2.3:o:microsoft:windows_11_25h2:*:*:*:*:*:*:x64:* Versions before 10.0.26200.9711 Vulnerable ·Microsoft
  • cpe:2.3:o:microsoft:windows_11_26h2:*:*:*:*:*:*:arm64:* Versions before 10.0.26300.9711 Vulnerable ·Microsoft
  • cpe:2.3:o:microsoft:windows_11_26h2:*:*:*:*:*:*:x64:* Versions before 10.0.26300.9711 Vulnerable ·Microsoft
  • cpe:2.3:o:microsoft:windows_server_2025:*:*:*:*:*:*:x64:* Versions before 10.0.26100.33650 Vulnerable ·Microsoft

Remediation

Install the fixed versions: Windows 11 Version 24H2 10.0.26100.9711, Windows 11 Version 25H2 10.0.26200.9711, Windows 11 Version 26H2 10.0.26300.9711, and Windows Server 2025 (including Server Core installation) 10.0.26100.33650.

Written with Claude Haiku 5.5 from the sources below · 2026-10-28

  • Fix · CNA Windows 11 Version 24H2 (Microsoft) Fixed in 10.0.26100.9711
  • Fix · CNA Windows 11 Version 25H2 (Microsoft) Fixed in 10.0.26200.9711
  • Fix · CNA Windows 11 Version 26H2 (Microsoft) Fixed in 10.0.26300.9711
  • Fix · CNA Windows Server 2025 (Microsoft) Fixed in 10.0.26100.33650
  • Fix · CNA Windows Server 2025 (Server Core installation) (Microsoft) Fixed in 10.0.26100.33650

Timeline

  1. 2026-10-13 Threatist record created from CVE-2026-83903
  2. 2026-10-13 Alias added: GHSA-9268-6277-cgg6

References

Patch 1

  • TI-2026-26194 Windows Internet Key Exchange (IKE) Service Extensions Remote Code Execution Vulnerability KEVCVSS 3.1CRITICAL 9.8
  • TI-2026-73128 Windows Shell Security Feature Bypass Vulnerability KEVCVSS 3.1HIGH 8.8
  • TI-2026-17367 MSHTML Framework Security Feature Bypass Vulnerability KEVCVSS 3.1HIGH 8.8
  • TI-2026-17364 Windows Shell Security Feature Bypass Vulnerability KEVCVSS 3.1HIGH 8.8
  • TI-2025-24062 Windows SMB Client Elevation of Privilege Vulnerability KEVCVSS 3.1HIGH 8.8
  • TI-2025-24042 Internet Shortcut Files Remote Code Execution Vulnerability KEVCVSS 3.1HIGH 8.8
See all 3558 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences