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MicrosoftCVE-2026-62734

Microsoft Windows Telephony Service: race condition

High7.0CVE-2026-62734 · Published Aug 11, 2026 · updated Aug 18, 2026

Concurrent execution using shared resource with improper synchronization ('race condition') in Windows Telephony Service allows an authorized attacker to elevate privileges locally.

Microsoft advisory

Affected versions

PackageAffectedFixed in
Windows 10 Version 1607
Product
>= 10.0.14393.0, < 10.0.14393.941810.0.14393.9418
Windows 10 Version 1809
Product
>= 10.0.17763.0, < 10.0.17763.912110.0.17763.9121
Windows 10 Version 21H2
Product
>= 10.0.19044.0, < 10.0.19044.766310.0.19044.7663
Windows 10 Version 22H2
Product
>= 10.0.19045.0, < 10.0.19045.766310.0.19045.7663
Windows 11 Version 23H2
Product
>= 10.0.22631.0, < 10.0.22631.751710.0.22631.7517
Windows 11 Version 24H2
Product
>= 10.0.26100.0, < 10.0.26100.916810.0.26100.9168
Windows 11 Version 25H2
Product
>= 10.0.26200.0, < 10.0.26200.916810.0.26200.9168
Windows 11 version 23H2
Product
>= 10.0.22631.0, < 10.0.22631.751710.0.22631.7517
Windows 11 version 26H1
Product
>= 10.0.28000.0, < 10.0.28000.270410.0.28000.2704
Windows Server 2012
Product
>= 6.2.9200.0, < 6.2.9200.262806.2.9200.26280
Windows Server 2012 (Server Core installation)
Product
>= 6.2.9200.0, < 6.2.9200.262806.2.9200.26280
Windows Server 2012 R2
Product
>= 6.3.9600.0, < 6.3.9600.233386.3.9600.23338
Details and references
CVSS 3.1
CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H
Severity from
the vendor (its own CVE record or advisory)
Weakness
CWE-362, CWE-416

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