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Integer underflow in Windows Failover Cluster allows denial of service

Priority MEDIUM 41CWE-191Published · Updated

Key facts

Attack vector
Network
Privileges required
None
User interaction
None
Attack complexity
Low
Impact type
Denial of service
Confidentiality · integrity · availability
None · None · High
Fix status
Fixed

Attack profile from CVSS 3.1 · CNA. Fix status from CNA. Impact type from CWE-191 and the CVSS impact.

Summary

Windows Server 2019 from 10.0.17763.0 before 10.0.17763.9376, Windows Server 2022 from 10.0.20348.0 before 10.0.20348.5761, and Windows Server 2025 from 10.0.26100.0 before 10.0.26100.33650 are affected, including Server Core installations. An integer underflow (CWE-191) in Windows Failover Cluster lets an unauthorized remote attacker deny service without privileges or user interaction.

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

Description from the CNA

Integer underflow (wrap or wraparound) in Windows Failover Cluster allows an unauthorized attacker to deny service over a network.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.01273 70th percentileScored 2026-11-07
Fix Fixed Windows Server 2019 (Microsoft): 10.0.17763.9376Windows Server 2019 (Server Core installation) (Microsoft): 10.0.17763.9376+3 more products

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
None
Automatable
Yes
Technical impact
Partial

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 Server 201910.0.17763.0 to before 10.0.17763.937610.0.17763.9376Patch availableCNA
MicrosoftWindows Server 2019 (Server Core installation)10.0.17763.0 to before 10.0.17763.937610.0.17763.9376Patch availableCNA
MicrosoftWindows Server 202210.0.20348.0 to before 10.0.20348.576110.0.20348.5761Patch 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 Server 2019 VendorMicrosoft Affected 10.0.17763.0 to before 10.0.17763.9376 Fixed in 10.0.17763.9376 Patch available CNA
  • Windows Server 2019 (Server Core installation) VendorMicrosoft Affected 10.0.17763.0 to before 10.0.17763.9376 Fixed in 10.0.17763.9376 Patch available CNA
  • Windows Server 2022 VendorMicrosoft Affected 10.0.20348.0 to before 10.0.20348.5761 Fixed in 10.0.20348.5761 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 · 3

CPEVersionsRoleVendor
cpe:2.3:o:microsoft:windows_server_2019:*:*:*:*:*:*:x64:*before 10.0.17763.9376VulnerableMicrosoft
cpe:2.3:o:microsoft:windows_server_2022:*:*:*:*:*:*:x64:*before 10.0.20348.5761VulnerableMicrosoft
cpe:2.3:o:microsoft:windows_server_2025:*:*:*:*:*:*:x64:*before 10.0.26100.33650VulnerableMicrosoft
  • cpe:2.3:o:microsoft:windows_server_2019:*:*:*:*:*:*:x64:* Versions before 10.0.17763.9376 Vulnerable ·Microsoft
  • cpe:2.3:o:microsoft:windows_server_2022:*:*:*:*:*:*:x64:* Versions before 10.0.20348.5761 Vulnerable ·Microsoft
  • cpe:2.3:o:microsoft:windows_server_2025:*:*:*:*:*:*:x64:* Versions before 10.0.26100.33650 Vulnerable ·Microsoft

Remediation

Apply the fixed builds: 10.0.17763.9376 for Windows Server 2019 (including Server Core installation), 10.0.20348.5761 for Windows Server 2022, and 10.0.26100.33650 for Windows Server 2025 (including Server Core installation).

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

  • Fix · CNA Windows Server 2019 (Microsoft) Fixed in 10.0.17763.9376
  • Fix · CNA Windows Server 2019 (Server Core installation) (Microsoft) Fixed in 10.0.17763.9376
  • Fix · CNA Windows Server 2022 (Microsoft) Fixed in 10.0.20348.5761
  • 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-2026-102192
  2. 2026-10-13 Alias added: GHSA-m36g-9wgq-rhw2
  3. 2026-10-14 CISA SSVC decision points changed
  4. 2026-10-14 Priority changed: MEDIUM → LOW
  5. 2026-10-14 Priority changed: LOW → MEDIUM

References

  • TI-2026-26194 Windows Internet Key Exchange (IKE) Service Extensions Remote Code Execution Vulnerability KEVCVSS 3.1CRITICAL 9.8
  • TI-2025-36863 Windows Server Update Service (WSUS) Remote Code Execution Vulnerability KEVCVSS 3.1CRITICAL 9.8
  • TI-2020-01431 Netlogon Elevation of Privilege Vulnerability KEVCVSS 3.1CRITICAL 10.0
  • TI-2020-01310 Improper input validation in Microsoft Windows Server KEVCVSS 3.1CRITICAL 10.0
  • 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
See all 6455 →

Sources