Chrome EUVD-2025-18417

This vulnerability presents critical real-world risk despite requiring local access. The CVSS vector (AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H) indicates network accessibility with low complexity and no privileges required, suggesting the local attack vector may be chained with remote exploitation. The confidentiality, integrity, and availability impacts are all HIGH, enabling complete system compromise. On managed Chrome devices, this is particularly severe because: (1) it circumvents enterprise extension policies designed to enforce security controls, (2) Developer Mode access enables further system modifications, (3) arbitrary extension loading enables persistent malware installation and data exfiltration. EPSS probability should be evaluated, but the combination of enterprise targeting, tool availability (ExtHang3r/ExtPrint3r), and policy bypass makes this a high-priority vulnerability. Organizations with managed Chrome device deployments face significant risk. KEV status and active exploitation reports would elevate priority further.

An attacker with local access to a managed Chrome OS device (employee, contractor, or physical access) runs ExtHang3r or ExtPrint3r tools to exploit the extension management permission bypass. Step 1: The attacker disables security-critical extensions (e.g., content filtering, data loss prevention) via the vulnerability. Step 2: The attacker accesses Developer Mode without administrative approval, bypassing device policies. Step 3: The attacker loads a malicious extension that exfiltrates corporate data, intercepts credentials, or establishes persistence. Step 4: If the device is on a corporate network, the attacker pivots to other systems using compromised credentials or network access. On managed devices, this is particularly severe because enterprise policies should prevent such actions. The low complexity and availability of exploitation tools (ExtHang3r/ExtPrint3r) suggest this vulnerability may already be actively exploited or will be shortly. Proof-of-concept code availability would be confirmed in security research disclosures and exploit databases.