Heap-based buffer overflow in Microsoft Windows and Windows Server - CVE-2026-83921
Published: October 14, 2026
Vulnerability identifier: #VU155064
CSH Severity: Low
CVSS v4: 7.3 [CVSS:4.0/AV:L/AC:L/AT:P/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N]
CVE-ID: CVE-2026-83921
CWE-ID: CWE-122
Exploitation vector: Local access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a local user to escalate privileges to SYSTEM.
The vulnerability exists due to a heap-based buffer overflow in Microsoft Windows Search Component when exploited locally. A local user can exploit this flaw to escalate privileges to SYSTEM.
Successful exploitation requires specific conditions, such as particular protocol settings or configurations, which the advisory does not identify.
Affected software
Microsoft Windows
Windows Server
Windows Server
How to mitigate CVE-2026-83921
Install security update from vendor's website.
Microsoft Windows - addressed in versions 10 21H2 10.0.19044.7807, 10 1607 10.0.14393.9612, 10 1809 10.0.17763.9376, 11 23H2 10.0.22631.7652, 11 24H2 10.0.26100.9711, 11 25H2 10.0.26200.9711, 11 26H1 10.0.28000.3231
Windows Server - addressed in versions 2012 R2 6.3.9600.23470, 2012 6.2.9200.26434, 2016 10.0.14393.9612, 2019 10.0.17763.9376, 2022 10.0.20348.5761, 2025 10.0.26100.33650
Windows Server - addressed in versions 2012 R2 6.3.9600.23470, 2012 6.2.9200.26434, 2016 10.0.14393.9612, 2019 10.0.17763.9376, 2022 10.0.20348.5761, 2025 10.0.26100.33650