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Description

Time-of-check time-of-use (toctou) race condition in Windows Kernel Memory allows an authorized attacker to elevate privileges locally.

PUBLISHED Reserved 2025-12-03 | Published 2026-01-13 | Updated 2026-02-22 | 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-367: Time-of-check Time-of-use (TOCTOU) Race Condition

CWE-122: Heap-based Buffer Overflow

Product status

10.0.14393.0 (custom) before 10.0.14393.8783
affected

10.0.17763.0 (custom) before 10.0.17763.8276
affected

10.0.19044.0 (custom) before 10.0.19044.6809
affected

10.0.19045.0 (custom) before 10.0.19045.6809
affected

10.0.22631.0 (custom) before 10.0.22631.6491
affected

10.0.22631.0 (custom) before 10.0.22631.6491
affected

10.0.26100.0 (custom) before 10.0.26100.7623
affected

10.0.26200.0 (custom) before 10.0.26200.7623
affected

6.3.9600.0 (custom) before 6.3.9600.22968
affected

6.3.9600.0 (custom) before 6.3.9600.22968
affected

10.0.14393.0 (custom) before 10.0.14393.8783
affected

10.0.14393.0 (custom) before 10.0.14393.8783
affected

10.0.17763.0 (custom) before 10.0.17763.8276
affected

10.0.17763.0 (custom) before 10.0.17763.8276
affected

10.0.20348.0 (custom) before 10.0.20348.4648
affected

10.0.25398.0 (custom) before 10.0.25398.2092
affected

10.0.26100.0 (custom) before 10.0.26100.32230
affected

10.0.26100.0 (custom) before 10.0.26100.32230
affected

References

msrc.microsoft.com/update-guide/vulnerability/CVE-2026-20809 (Windows Kernel Memory Elevation of Privilege Vulnerability) vendor-advisory patch

cve.org (CVE-2026-20809)

nvd.nist.gov (CVE-2026-20809)

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