CVE-2026-83505: Windows Setup Files Cleanup Elevation of Privilege Vulnerability
Time-of-check time-of-use (toctou) race condition in Windows Setup Files Cleanup allows an authorized attacker to elevate privileges locally.
Other sources
Windows Setup Files Cleanup Elevation of Privilege Vulnerability
— Microsoft
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Upgrade
Upgrade to a fixed release to a version that resolves this vulnerability.
Fixed in 10.0.19044.7807Patch KB5126657 - Upgrade
Upgrade to a fixed release to a version that resolves this vulnerability.
Fixed in 10.0.14393.9612Patch KB5126868 - Upgrade
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Fixed in 10.0.26100.33650Patch KB5126646 - Upgrade
Upgrade to a fixed release to a version that resolves this vulnerability.
Fixed in 10.0.26100.9711Patch KB5127648 - Upgrade
Upgrade to a fixed release to a version that resolves this vulnerability.
Fixed in 10.0.28000.3231Patch KB5127646 - Upgrade
Upgrade to a fixed release to a version that resolves this vulnerability.
Fixed in 10.0.26200.9711Patch KB5127648 - Upgrade
Upgrade to a fixed release to a version that resolves this vulnerability.
Fixed in 10.0.17763.9376Patch KB5126651 - Upgrade
Upgrade to a fixed release to a version that resolves this vulnerability.
Fixed in 10.0.26300.9711Patch KB5127648 - Upgrade
Upgrade to a fixed release to a version that resolves this vulnerability.
Fixed in 10.0.22631.7652Patch KB5126653 - Upgrade
Upgrade to a fixed release to a version that resolves this vulnerability.
Fixed in 10.0.20348.5761Patch KB5126655
Event History
Frequently Asked Questions
Who is exposed to this issue?
Systems running the listed Microsoft Windows 10, Windows 11, Windows Server 2016, Windows Server 2019, Windows Server 2022, or Windows Server 2025 products may be exposed. Exploitation is local rather than network-based.
What access does an attacker need to exploit it?
An attacker must already be authorized on the affected system and have low privileges. The attack requires winning a time-of-check time-of-use race condition; no user interaction is required.
What is the likely impact of successful exploitation?
A successful attacker can elevate privileges locally. The supplied severity vector indicates high potential impact to confidentiality, integrity, and availability.
How can defenders determine whether a system is affected?
Review whether the system runs one of the listed Windows products and whether Windows Setup Files Cleanup is present or used in its environment. The provided information does not include affected build numbers, update identifiers, or a detection method.