A local privilege escalation vulnerability (CVE-2026-69859, CVSS 7.0 High) exists in the Windows USB Audio Class driver (usbaudio.sys) due to a time-of-check time-of-use (TOCTOU) race condition combined with an integer underflow. An authenticated attacker could exploit this to gain SYSTEM privileges locally, though successful exploitation is complex and less likely. Microsoft has released security updates to address this vulnerability; administrators should apply the relevant patches for their Windows versions.
We use optional cookies to improve your experience on our websites, such as through social media connections, and to display personalized advertising based on your online activity. If you reject optional cookies, only cookies necessary to provide you the services will be used. You may change your selection by clicking “Manage Cookies” at the bottom of the page. Privacy Statement Third-Party Cookies AcceptRejectManage cookies MSRC Customer Guidance Security Update Guide Vulnerabilities CVE-2026-69859 Windows USB Audio Class driver (usbaudio.sys) Elevation of Privilege Vulnerability New On this page CVE-2026-69859 Subscribe RSS PowerShell API CSAF Security Vulnerability Released: Sep 8, 2026 Assigning CNA Microsoft CVE.org link CVE-2026-69859 Impact Elevation of Privilege Max Severity Important Weakness CWE-367: Time-of-check Time-of-use (TOCTOU) Race Condition CWE-191: Integer Underflow (Wrap or Wraparound) CVSS Source Microsoft Vector String CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C Metrics CVSS:3.1 7.0 / 6.1 Base score metrics: 7.0 / Temporal score metrics: 6.1 Expand all Collapse all Metric Value Base score metrics(8) Attack Vector Local Attack Complexity High Privileges Required Low User Interaction None Scope Unchanged Confidentiality High Integrity High Availability High Temporal score metrics(3) Exploit Code Maturity Unproven Remediation Level Official Fix Report Confidence Confirmed Please see Common Vulnerability Scoring System for more information on the definition of these metrics. Executive Summary Time-of-check time-of-use (toctou) race condition in Windows USB Audio Class driver (usbaudio.sys) allows an authorized attacker to elevate privileges locally. Exploitability The following table provides an exploitability assessment for this vulnerability at the time of original publication. Publicly disclosed No Exploited No Exploitability assessment Exploitation Less Likely FAQ According to the CVSS metric, the attack complexity is high (AC:H). What does that mean for this vulnerability? Successful exploitation of this vulnerability requires an attacker to have a deep understanding of the system. Successful exploitation is not guaranteed and depends on a combination of factors that might include the environment, system configuration, and the presence of additional security measures. What privileges could be gained by an attacker who successfully exploited this vulnerability? An attacker who successfully exploited this vulnerability could gain SYSTEM privileges. Acknowledgements Seung Chan Kim https://mylostchristmas.tistory.com/20 Microsoft recognizes the efforts of those in the security community who help us protect customers through coordinated vulnerability disclosure. See Acknowledgements for more information. Security Updates To determine the support lifecycle for your software, see the Microsoft Support Lifecycle. Release date Descending Edit columns Download Filters Product Family Max Severity Impact Platform Clear Release date Product Platform Impact Max Severity Article Download Build Number Assigning CNA Loading... Disclaimer The information provided in the Microsoft Knowledge Base is provided "as is" without warranty of any kind. Microsoft disclaims all warranties, either express or implied, including the warranties of merchantability and fitness for a particular purpose. In no event shall Microsoft Corporation or its suppliers be liable for any damages whatsoever including direct, indirect, incidental, consequential, loss of business profits or special damages, even if Microsoft Corporation or its suppliers have been advised of the possibility of such damages. Some states do not allow the exclusion or limitation of liability for consequential or incidental damages so the foregoing limitation may not apply. Revisions version revisionDate description 1.0 Sep 8, 2026 Information published. How satisfied are you with the MSRC Security Update Guide? Rating Broken Bad Below average Average Great! Your Privacy Choices Consumer Health Privacy Privacy & Cookies