SB20260819147 - Race condition in Microsoft Windows Telephony service

Description

This security bulletin contains information about 1 vulnerability.

1) Race condition (CVE-ID: CVE-2026-62727)

CWE-ID: CWE-362 - Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition')

CVSSv4: 7.3 [CVSS:4.0/AV:L/AC:L/AT:P/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N]

The vulnerability allows a local user to escalate privileges.

The vulnerability exists due to concurrent execution using shared resource with improper synchronization ('race condition') in Windows Telephony Service when handling concurrent execution on a shared resource. A local user can win a race condition to escalate privileges.

Successful exploitation could grant SYSTEM privileges.

Remediation

Install update from vendor's website.

References

• https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2026-62727
• https://support.microsoft.com/help/5120238