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Description

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

PUBLISHED Reserved 2025-12-11 | Published 2026-02-10 | Updated 2026-02-23 | Assigner microsoft




HIGH: 7.8CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C

Problem types

CWE-122: Heap-based Buffer Overflow

Product status

10.0.14393.0 (custom) before 10.0.14393.8868
affected

10.0.17763.0 (custom) before 10.0.17763.8389
affected

10.0.19044.0 (custom) before 10.0.19044.6937
affected

10.0.19045.0 (custom) before 10.0.19045.6937
affected

10.0.22631.0 (custom) before 10.0.22631.6649
affected

10.0.22631.0 (custom) before 10.0.22631.6649
affected

10.0.26100.0 (custom) before 10.0.26100.7840
affected

10.0.26200.0 (custom) before 10.0.26200.7840
affected

6.2.9200.0 (custom) before 6.2.9200.25923
affected

6.2.9200.0 (custom) before 6.2.9200.25923
affected

6.3.9600.0 (custom) before 6.3.9600.23022
affected

6.3.9600.0 (custom) before 6.3.9600.23022
affected

10.0.14393.0 (custom) before 10.0.14393.8868
affected

10.0.14393.0 (custom) before 10.0.14393.8868
affected

10.0.17763.0 (custom) before 10.0.17763.8389
affected

10.0.17763.0 (custom) before 10.0.17763.8389
affected

10.0.20348.0 (custom) before 10.0.20348.4773
affected

10.0.25398.0 (custom) before 10.0.25398.2149
affected

10.0.26100.0 (custom) before 10.0.26100.32370
affected

10.0.26100.0 (custom) before 10.0.26100.32370
affected

References

msrc.microsoft.com/update-guide/vulnerability/CVE-2026-21239 (Windows Kernel Elevation of Privilege Vulnerability) vendor-advisory patch

cve.org (CVE-2026-21239)

nvd.nist.gov (CVE-2026-21239)

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