CVE-2026-12468: Chrome macOS Sandbox Escape via Race Condition in Updater

Technical summary

CVE-2026-12468 is a race condition (CWE-362) in Chrome's update mechanism on macOS that permits sandbox escape when an attacker controls the renderer process. The Chromium security team classified this as High severity. The race window occurs during the update process, where an attacker with renderer-level code execution can manipulate timing to trigger a privileged operation outside the sandbox boundary. The attack surface is conditional—it requires prior renderer compromise via a crafted HTML document—but once that foothold exists, the race condition provides a reliable path to unrestricted system access. The CVSS 3.1 score of 8.3 reflects the high impact (confidentiality, integrity, availability all compromised) weighted against the requirement for user interaction and difficult attack complexity.

Business impact

Organizations running Chrome on macOS face a two-stage attack risk: first, users must visit a malicious site or be served crafted content that exploits a renderer vulnerability; second, if that succeeds, the sandbox escape grants attackers unfiltered access to the user's system. For enterprise environments, this means an attacker could pivot from a compromised browser process to steal credentials, install malware, exfiltrate data, or move laterally across the network. The practical impact is significant for businesses where macOS is prevalent (design, creative services, tech companies) and where employees browse untrusted content. Patching is not merely a security hygiene task—it's essential to eliminate a direct privilege escalation path.

Affected systems

Google Chrome on Apple macOS running version 149.0.7827.155 or earlier. The vulnerability is macOS-specific; Chrome on Windows and Linux have different update mechanisms and are not affected by this particular race condition. Organizations should inventory macOS devices running Chrome and prioritize updates across both managed and unmanaged machines where feasible.

Exploitability

Exploitation requires two preconditions: (1) the attacker must first compromise Chrome's renderer process by delivering a crafted HTML page to a victim, and (2) the victim must interact with the page in a way that triggers the malicious code. Once renderer access is achieved, exploiting the race condition to escape the sandbox is technically straightforward—it's a timing-based attack with a deterministic window. The attack does not require special privileges, valid credentials, or administrative intervention, but the multi-stage nature and dependence on prior renderer compromise make this a targeted rather than mass-exploitation scenario in the near term. The fact that this is not yet listed on CISA's Known Exploited Vulnerabilities (KEV) catalog suggests active exploitation is limited, though the High severity rating and straightforward race-condition mechanics mean exploit code will likely emerge.

Remediation

Update Google Chrome on macOS to version 149.0.7827.155 or later. Chrome's automatic update feature should deploy the patch, but verify completion by checking the About Chrome menu (Chrome > About Google Chrome on macOS). For enterprise deployments, use MDM or group policy to enforce updates if auto-update is disabled. Confirm the browser has restarted to apply the patch—the version number in chrome://version/ should reflect the patched release. No workarounds exist for this race condition; patching is the only mitigation.

Patch guidance

Verify the patch version against Google's official Chrome release notes for macOS. End users should check chrome://version/ to confirm they are running 149.0.7827.155 or later. Enterprise administrators should deploy updates through their MDM solution and audit compliance within 30 days. Test the patched version in a representative environment before full rollout if your organization gates Chrome updates. Google does not require a system restart on macOS for Chrome updates to take effect, but the browser must be closed and reopened; some users may need a reminder if they keep long-running browser sessions.

Detection guidance

Monitor Chrome version telemetry from macOS devices using your endpoint detection and response (EDR) or mobile device management (MDM) platform. Log and alert on any Chrome processes running versions below 149.0.7827.155 after your patch deadline. If detailed logging is available, watch for unusual renderer process behavior followed by file system or privileged operations—a sandbox escape would show privilege elevation anomalies. At the network level, monitor for unusual egress from compromised macOS hosts that might indicate lateral movement post-exploitation. However, the race condition itself may be difficult to observe in logs; focus on version compliance and behavioral anomalies as primary signals.

Why prioritize this

This vulnerability merits high priority due to its High CVSS score (8.3), macOS-specific attack chain targeting a common browser, and the availability of a complete patch. While the attack requires initial renderer compromise, the sandbox escape is a critical privilege escalation that, if successful, gives attackers unfettered system access. In organizations with significant macOS user bases (tech, creative, financial services), the risk of targeted attacks using this chain is meaningful. The absence of an active KEV listing should not lower your priority—it indicates detection of active exploitation is still emerging, not that the vulnerability is less severe.

Risk score, explained

The CVSS 3.1 score of 8.3 (High) reflects: high impact across all three security objectives (confidentiality, integrity, availability are all marked High), network-based attack vector, user interaction required (lowering the score from Critical), and a high attack complexity due to the race condition's timing requirements. The score appropriately captures that this is a serious privilege escalation, not a simple remote code execution; the two-stage attack chain and complexity factors prevent a Critical rating, but the consequences—full system compromise—justify the High category.

Frequently asked questions