CVE-2023-38146: Microsoft Windows 11 version 21H2 · Time-of-check Time-of-use (TOCTOU) Race Condition
Affects Microsoft Windows 11 version 21H2Source CVE Database V5
Not known to be exploited · public exploit available (Metasploit) · 37% EPSS · CVSS 8.8 High.
Data as of 25 Oct 2026, 19:02 UTC
- EPSS
- 37.3% chance of exploitation in 30 days – higher than 98% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H/E:U/RL:O/RC:CExploitation evidence
Disclosed: evidence found.
CVE published 12 Sep 2023
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: evidence found.
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 2026-10-25.
What to do
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| Microsoft Windows 11 version 21H2 | Affected
| Fixed in– |
AI-suggested
1. Apply official Microsoft security patches immediately once they become available to address CVE-2023-38146. 2. Until patches are released, restrict the ability to apply or download themes from untrusted or external sources by implementing group policies that limit theme changes. 3. Educate users to avoid opening or applying themes received from unknown or suspicious sources to reduce the risk of user interaction exploitation. 4. Deploy endpoint detection and response (EDR) solutions to monitor for unusual theme-related activities or race condition exploitation attempts. 5. Use application whitelisting to prevent unauthorized execution of code triggered by malicious themes. 6. Regularly update antivirus and antimalware signatures to detect potential payloads delivered via this vulnerability. 7. Implement network-level controls to block or monitor traffic associated with theme file distribution from untrusted networks. 8. Conduct phishing awareness campaigns to reduce the likelihood of users being tricked into applying malicious themes. 9. Review and tighten permissions on theme-related system components to minimize exploitation windows. 10. Maintain robust backup and recovery procedures to mitigate the impact of potential ransomware or destructive attacks leveraging this vulnerability.
Description
Windows Themes Remote Code Execution Vulnerability