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No exploitation reportedFix available

CVE-2026-20816

No exploitation reported by the sources we read.

  • Published2026-01-13
  • WeaknessCWE-367

Am I affected?

With a domain, we read the version its public headers and pages expose. A distribution build can carry the fix under an older number.

Description

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

Timeline

dates in UTC
  1. 2026-01-1318:16CVE publishedNVD

Versions per branch

NVD
Microsoft windows server 2008
BranchAffectedFixed in
—all versionsno fix published
—= r2no fix published
Microsoft windows server 2012
BranchAffectedFixed in
—all versionsno fix published
—= r2no fix published
Microsoft windows 10 1607
BranchAffectedFixed in
10.0< 10.0.14393.878310.0.14393.8783

11 more products in the sources.

as publishedRanges as NVD and OSV publish them; a distribution’s build can be fixed under an older number.

Products declared by the CNA24 products

As microsoft, the CNA that assigned this CVE, declared them in the CVE record; versions as written.

  • Microsoft Windows 10 Version 1607

    platforms: 32-bit Systems, x64-based Systems

    Affected
    • ≥ 10.0.14393.0, < 10.0.14393.8783fixed in 10.0.14393.8783custom
  • Microsoft Windows 10 Version 1809

    platforms: 32-bit Systems, x64-based Systems

    Affected
    • ≥ 10.0.17763.0, < 10.0.17763.8276fixed in 10.0.17763.8276custom
  • Microsoft Windows 10 Version 21H2

    platforms: 32-bit Systems, ARM64-based Systems, x64-based Systems

    Affected
    • ≥ 10.0.19044.0, < 10.0.19044.6809fixed in 10.0.19044.6809custom
  • Microsoft Windows 10 Version 22H2

    platforms: 32-bit Systems, ARM64-based Systems, x64-based Systems

    Affected
    • ≥ 10.0.19045.0, < 10.0.19045.6809fixed in 10.0.19045.6809custom
  • Microsoft Windows 11 version 22H3

    platforms: ARM64-based Systems

    Affected
    • ≥ 10.0.22631.0, < 10.0.22631.6491fixed in 10.0.22631.6491custom
  • Microsoft Windows 11 Version 23H2

    platforms: x64-based Systems

    Affected
    • ≥ 10.0.22631.0, < 10.0.22631.6491fixed in 10.0.22631.6491custom

18 more products in the CVE record.

Source: the CNA record (CVE Program), © The MITRE Corporation,CVE Terms of UseCVE recordupdated 2026-04-01

Fix

Advisories and patches

Detection

Nuclei template
none so far
ProjectDiscovery
Exploit-DB
no entry
Exploit-DB
Proof of concept
Metasploit modules
none listed
Metasploit Framework

Sources

Identifiers

Technical details

CVSS v3 Vector
CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H
Published
2026-01-13
Last Modified
2026-07-30
NVD status
Analyzed
GitHub Advisory
GHSA-73xx-3f4h-3mv2

Frequently asked questions

What is CVE-2026-20816?

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

Is CVE-2026-20816 actively exploited?

Active exploitation of CVE-2026-20816 has not been confirmed. Its EPSS score was 2.4% on 2026-11-08, the estimated probability of exploitation in the next 30 days.

What is the CVSS score for CVE-2026-20816?

CVE-2026-20816 has a CVSS v3 base score of 7 (HIGH severity), with vector string CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H.

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