SYSTEM privilege escalation via Telephony Service race
Published Aug 11, 2026 · Updated Aug 25, 2026
A race condition in Microsoft Windows Telephony Service allows local users with low privileges to gain SYSTEM privileges. Concurrent access to a shared resource can leave an object in use after it is freed, but Microsoft has not disclosed the affected function or trigger. Exploitation requires existing low-privilege local access and winning a high-complexity race; successful exploitation grants SYSTEM control.
Summary
What happened
A race condition in Microsoft Windows Telephony Service allows local users with low privileges to gain SYSTEM privileges. Concurrent access to a shared resource can leave an object in use after it is freed, but Microsoft has not disclosed the affected function or trigger. Exploitation requires existing low-privilege local access and winning a high-complexity race; successful exploitation grants SYSTEM control.
The record
- CVE
- CVE-2026-62729
- Published
- Aug 11, 2026
- Updated
- Aug 25, 2026
- Vendor
- Microsoft
- Product
- Windows Server 2019
- Classifications
- CWE-416, CWE-362, T1068
- Attack vector
- local
- Privileges
- authenticated
Timeline
How it unfolded
- Aug 11, 2026CVE publishedPublication date reported by the CVE source.
- Aug 25, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=10.0.17763.0 <10.0.17763.9121
What conditions does exploitation require?
What is affected?
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.
Weakness, pattern, technique
Public exploit references
No public exploit references are available in this record.
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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