CVE-2026-20809 — Heap-based Buffer Overflow in Microsoft Windows 10 Version 1607

CWE-122 — Heap-based Buffer OverflowCWE-367 — Time-of-check Time-of-use (TOCTOU) Race Condition5 documents5 sources
Severity
7.8HIGHNVD
EPSS
0.0%
top 92.56%
CISA KEV
Not in KEV
Exploit
No known exploits
Affected products
22
Microsoft Windows 10 Version 1607Microsoft Windows 10 Version 1809Microsoft Windows 10 Version 21h2+19 more
Timeline
PublishedJan 13

Description

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

CVSS vector

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:HExploitability: 1.8 | Impact: 5.9

Affected Packages21 packages

▶NVDmicrosoft/windows< 10.0.14393.8783+5
▶NVDmicrosoft/windows_10_1607< 10.0.14393.8783
▶NVDmicrosoft/windows_10_1809< 10.0.17763.8276
▶NVDmicrosoft/windows_10_21h2< 10.0.19044.6809
▶NVDmicrosoft/windows_10_22h2< 10.0.19045.6809

🔴Vulnerability Details

2
GHSA
GHSA-637q-m772-j8h6: Time-of-check time-of-use (toctou) race condition in Windows Kernel Memory allows an authorized attacker to elevate privileges locally↗2026-01-13
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CVEList
Windows Kernel Memory Elevation of Privilege Vulnerability↗2026-01-13
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📋Vendor Advisories

1
Microsoft
Windows Kernel Memory Elevation of Privilege Vulnerability↗2026-01-13
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🕵️Threat Intelligence

1
Wiz
CVE-2026-20809 Impact, Exploitability, and Mitigation Steps | Wiz↗
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CVE-2026-20809 — Heap-based Buffer Overflow | cvebase