CVE-2026-20809CWE-122CWE-367

CVE-2026-20809

High · published January 13, 2026

CVSS v3.1
7.8
EPSS
0%
Percentile
28.5
In the wild
Unconfirmed
What it is

⚡ A sneaky race condition in the Windows Kernel Memory could let an authorized attacker elevate privileges locally with a well-timed exploit! 🚀 Think of this as a relay race where one runner has a split-second to swap the baton—if they time it just right, they bypass security checks and claim the prize. It’s about getting into the inner circle before the door closes! If exploited, an attacker could gain elevated privileges, essentially granting them unrestricted access to sensitive areas of the system! This means they could install malicious software, manipulate system settings, or even take control of the device entirely—a disastrous situation for any system admin!

Put simply

Think of this as a relay race where one runner has a split-second to swap the baton—if they time it just right, they bypass security checks and claim the prize. It’s about getting into the inner circle before the door closes! This vulnerability is caused by a time-of-check time-of-use (TOCTOU) race condition, which arises when an attacker manipulates system resources between the moment they are checked and when they are used, allowing them to execute unauthorized actions.

What to do

If exploited, an attacker could gain elevated privileges, essentially granting them unrestricted access to sensitive areas of the system! This means they could install malicious software, manipulate system settings, or even take control of the device entirely—a disastrous situation for any system admin! To protect your systems, ensure you apply the latest security patches from Microsoft as soon as they are available. Regularly audit your permissions and monitor for suspicious activities to stay one step ahead of potential exploits. 🛡️ Don't sweat it—this is fixable! Stay proactive with your updates, and you'll keep your systems rock solid! 💪✨

The record
Technical detail
CVSS v3.1
7.8 · HIGH
Vector
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
CVSS v4.0
Not supplied
EPSS
0.00359 · 28.5th percentile
Weaknesses
CWE-122 · Heap-based Buffer Overflow; CWE-367 · Time-of-check Time-of-use (TOCTOU) Race Condition
Published
2026-01-13T23:16Z
Affected products (15)
ProductVersionsFixed in
microsoft/windows_10_1607< 10.0.14393.878310.0.14393.8783
microsoft/windows_10_1607< 10.0.14393.878310.0.14393.8783
microsoft/windows_10_1809< 10.0.17763.827610.0.17763.8276
microsoft/windows_10_1809< 10.0.17763.827610.0.17763.8276
microsoft/windows_10_21h2< 10.0.19044.680910.0.19044.6809
microsoft/windows_10_22h2< 10.0.19045.680910.0.19045.6809
microsoft/windows_11_23h2< 10.0.22631.649110.0.22631.6491
microsoft/windows_11_24h2< 10.0.26100.762310.0.26100.7623
microsoft/windows_11_25h2< 10.0.26200.762310.0.26200.7623
microsoft/windows_server_2012all versions—
microsoft/windows_server_2016< 10.0.14393.878310.0.14393.8783
microsoft/windows_server_2019< 10.0.17763.827610.0.17763.8276
microsoft/windows_server_2022< 10.0.20348.464810.0.20348.4648
microsoft/windows_server_2022_23h2< 10.0.25398.209210.0.25398.2092
microsoft/windows_server_2025< 10.0.26100.3223010.0.26100.32230
References (1)
EPSS history
Timeline
  • 13 JAN 17:56Z
    Windows Kernel Memory Elevation of Privilege Vulnerability
    cvelistv5