CVE-2026-20856

Summary

Improper input validation in Windows Server Update Service allows an unauthorized attacker to execute code over a network.

Affected Software

VendorProductVersion RangeStatus
MicrosoftWindows 10 Version 160710.0.14393.0 < 10.0.14393.8783affected
MicrosoftWindows 10 Version 180910.0.17763.0 < 10.0.17763.8276affected
MicrosoftWindows 10 Version 21H210.0.19044.0 < 10.0.19044.6809affected
MicrosoftWindows 10 Version 22H210.0.19045.0 < 10.0.19045.6809affected
MicrosoftWindows 11 version 22H310.0.22631.0 < 10.0.22631.6491affected
MicrosoftWindows 11 Version 23H210.0.22631.0 < 10.0.22631.6491affected
MicrosoftWindows 11 Version 24H210.0.26100.0 < 10.0.26100.7623affected
MicrosoftWindows 11 Version 25H210.0.26200.0 < 10.0.26200.7623affected
MicrosoftWindows Server 20126.2.9200.0 < 6.2.9200.25868affected
MicrosoftWindows Server 2012 (Server Core installation)6.2.9200.0 < 6.2.9200.25868affected
MicrosoftWindows Server 2012 R26.3.9600.0 < 6.3.9600.22968affected
MicrosoftWindows Server 2012 R2 (Server Core installation)6.3.9600.0 < 6.3.9600.22968affected
MicrosoftWindows Server 201610.0.14393.0 < 10.0.14393.8783affected
MicrosoftWindows Server 2016 (Server Core installation)10.0.14393.0 < 10.0.14393.8783affected
MicrosoftWindows Server 201910.0.17763.0 < 10.0.17763.8276affected
MicrosoftWindows Server 2019 (Server Core installation)10.0.17763.0 < 10.0.17763.8276affected
MicrosoftWindows Server 202210.0.20348.0 < 10.0.20348.4648affected
MicrosoftWindows Server 2022, 23H2 Edition (Server Core installation)10.0.25398.0 < 10.0.25398.2092affected
MicrosoftWindows Server 202510.0.26100.0 < 10.0.26100.32230affected
MicrosoftWindows Server 2025 (Server Core installation)10.0.26100.0 < 10.0.26100.32230affected

Weaknesses

  • CWE-20: CWE-20: Improper Input Validation

ADP Enrichment

CISA ADP Vulnrichment

  • SSVC:
  • Exploitation: none
    • Automatable: no
    • Technical Impact: total

References