CVE-2026-17709 is a race condition vulnerability in the Downloads feature of Google Chrome on Mac platforms before version 151.0.7922.72. An attacker who has already compromised the renderer process can exploit this race condition to perform a sandbox escape, thereby potentially gaining elevated privileges outside the browser sandbox. The vulnerability is recognized as critical by Chromium security and carries a high CVSS score of 9.6, indicating severe impact on confidentiality, integrity, and availability.

Successful exploitation allows a remote attacker with control over the renderer process to escape the sandbox environment, which can lead to full system compromise or unauthorized access to system resources beyond the browser's restrictions. This significantly increases the risk posed by any prior compromise of the renderer process.

Users should update Google Chrome on Mac to version 151.0.7922.72 or later, where this vulnerability is fixed. The vendor advisory confirms the availability of this update. No additional mitigation steps are indicated beyond applying this official fix.