CVE-2023-38146Public exploitNetwork attack vector

Remote code execution via theme DLL race

Published Sep 12, 2023 · Updated Oct 30, 2025

Remote code execution in Windows Themes in Microsoft Windows 11 allows remote attackers to execute code via a crafted theme file. ReviseVersionIfNecessary verifies an _vrf.dll file, closes it, and later reloads the path, allowing an SMB server to replace the signed file with a malicious DLL. A user must open the crafted theme or theme pack while the system can reach the attacker-controlled share, after which the DLL runs code in the user's context.

CVSS severity8.8
High
EPSS probability39.16%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Remote code execution in Windows Themes in Microsoft Windows 11 allows remote attackers to execute code via a crafted theme file. ReviseVersionIfNecessary verifies an _vrf.dll file, closes it, and later reloads the path, allowing an SMB server to replace the signed file with a malicious DLL. A user must open the crafted theme or theme pack while the system can reach the attacker-controlled share, after which the DLL runs code in the user's context.

The record

CVE
CVE-2023-38146
Published
Sep 12, 2023
Updated
Oct 30, 2025
Vendor
Microsoft
Product
Windows 11 version 21H2
Classifications
CWE-367, T1204.002, T1203
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Sep 12, 2023CVE publishedPublication date reported by the CVE source.
  2. Oct 30, 2025Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=10.0.0 <10.0.22000.2416

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Microsoft · Windows 11 version 21H2version=10.0.0 <10.0.22000.2416
Microsoft · Windows 11, version 22H2version=10.0.22621.0 <10.0.22621.2283

Published CVSS scores

8.8Microsoft CorporationCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-367Time-of-check Time-of-use (TOCTOU) Race Condition
T1204.002User Execution: Malicious File
T1203Exploitation for Client Execution

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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