Local privilege escalation via service race condition
Published Jun 9, 2026 · Updated Jun 9, 2026
Race condition in Microsoft Windows Telephony Service on affected Windows builds allows local users to elevate privileges on the host. Microsoft identifies improper synchronization of a shared resource but has not disclosed the resource, code path, or conflicting operation. Exploitation requires low-privileged local access and winning a high-complexity timing race, after which the attacker gains elevated control over the system.
Summary
What happened
Race condition in Microsoft Windows Telephony Service on affected Windows builds allows local users to elevate privileges on the host. Microsoft identifies improper synchronization of a shared resource but has not disclosed the resource, code path, or conflicting operation. Exploitation requires low-privileged local access and winning a high-complexity timing race, after which the attacker gains elevated control over the system.
The record
- CVE
- CVE-2026-42912
- Published
- Jun 9, 2026
- Updated
- Jun 9, 2026
- Vendor
- Microsoft
- Product
- Windows Server 2019
- Classifications
- CWE-362, T1068
- Attack vector
- local
- Privileges
- authenticated
Timeline
How it unfolded
- Jun 9, 2026CVE publishedPublication date reported by the CVE source.
- Jun 9, 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 <10.0.17763.8880
What conditions does exploitation require?
What is affected?
Published CVSS scores
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.
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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