CVE-2025-49737: 
NixOS vulnerability analysis and mitigation

CVE-2025-49737 is a race condition vulnerability in Microsoft Teams for macOS that allows an authorized local attacker to elevate privileges. The flaw stems from concurrent execution using a shared resource with improper synchronization (CWE-362). It affects Microsoft Teams for macOS versions prior to 25163.3001.3726.6503 and was publicly disclosed on July 8, 2025, as part of Microsoft's July 2025 Patch Tuesday. The vulnerability carries a CVSS v3.1 base score of 7.0 (High) (Microsoft MSRC).

The vulnerability is classified under CWE-362 (Concurrent Execution Using Shared Resource with Improper Synchronization), commonly known as a race condition. An attacker with low-privilege local access can exploit a time-of-check to time-of-use (TOCTOU) window — mapped to CAPEC-29 — by racing against a shared resource access in Microsoft Teams before proper synchronization controls are applied. Exploitation requires local access and low privileges but no user interaction, and the attack complexity is rated High, indicating that specific timing conditions must be met for successful exploitation (Microsoft MSRC).

Successful exploitation allows a locally authenticated attacker to escalate privileges within the Microsoft Teams application on macOS, with potential high impact to confidentiality, integrity, and availability of the affected system. An attacker could leverage elevated privileges to access sensitive system resources, modify application data, or disrupt Teams functionality. The scope is unchanged, meaning the impact is contained to the vulnerable component rather than extending to other system components (Microsoft MSRC).

As of the disclosure date, there is no public proof-of-concept exploit and no evidence of in-the-wild exploitation (Microsoft MSRC). The vulnerability is not listed in the CISA Known Exploited Vulnerabilities (KEV) catalog. The EPSS score is approximately 0.036%, reflecting a low probability of exploitation in the near term. No threat actor attribution has been reported.

Microsoft released a security update on July 8, 2025, addressing this vulnerability. Users should update Microsoft Teams for macOS to version 25163.3001.3726.6503 or later. As a general hardening measure, organizations should enforce the principle of least privilege to limit the impact of any local privilege escalation attempt and monitor for unusual privilege escalation activity on macOS endpoints (Microsoft MSRC).

The vulnerability was noted as part of Microsoft's July 2025 Patch Tuesday, which addressed 137 vulnerabilities in total. Security outlets including BleepingComputer, Rapid7, Sophos, and Zero Day Initiative covered the broader Patch Tuesday release, with CVE-2025-49737 receiving limited individual attention given its local-only attack vector and lack of active exploitation (BleepingComputer, ZDI Blog, Rapid7 Blog).