CVE-2025-49660: Windows Event Tracing Use After Free Vulnerability

Overview

CVE-2025-49660 is a critical vulnerability in the Windows Event Tracing system that could potentially lead to a system compromise or data leakage. This flaw allows an authorized attacker to elevate their privileges locally. Given the widespread use of Windows operating systems globally, this vulnerability could have significant consequences, affecting millions of users and enterprises. It is therefore crucial to understand its nature, scope, and potential remedies.

Vulnerability Summary

CVE ID: CVE-2025-49660
Severity: High (7.8 CVSS score)
Attack Vector: Local
Privileges Required: Low
User Interaction: Required
Impact: System compromise or data leakage

Affected Products

Product | Affected Versions

Windows | All versions up to date of discovery

How the Exploit Works

The exploit works by taking advantage of a use-after-free vulnerability in the Windows Event Tracing system. The attacker, already having low-level access, triggers a specific condition that allows them to use memory space that has been freed but not yet reallocated by the system. This can potentially lead to arbitrary code execution with elevated privileges, which could lead to system compromise or data leakage.

Conceptual Example Code

Let’s consider a conceptual example where an attacker might exploit this vulnerability. This could be a command run locally, which triggers the vulnerability:

C:\>wevtutil cl Security /bu:C:\Temp\backup.evtx
C:\>wevtutil epl Security C:\Temp\exploit.evtx /ow:true
C:\>wevtutil sl Security /e:true

In this example, the attacker first backs up the Security log (`wevtutil cl Security /bu:C:\Temp\backup.evtx`). Then, they overwrite it with an exploit log that contains malicious code (`wevtutil epl Security C:\Temp\exploit.evtx /ow:true`). Finally, they enable logging again (`wevtutil sl Security /e:true`), which triggers the use after free condition and executes the malicious code.
Please note that this is a conceptual and simplified example and does not represent an actual exploit.

Mitigation Guidance

To mitigate this vulnerability, the best course of action is to apply the vendor patch as soon as it is available. If a patch is not available or cannot be applied immediately, using a Web Application Firewall (WAF) or an Intrusion Detection System (IDS) could provide temporary mitigation. These systems can help detect unusual or malicious activity related to this vulnerability and stop it before it can cause harm. However, keep in mind that these are only temporary solutions and do not substitute for the vendor patch.