EUVD-2025-18417CVSS Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Lifecycle Timeline
4Description
Permissions Bypass in Extension Management in Google ChromeOS 16181.27.0 on managed Chrome devices allows a local attacker to disable extensions and access Developer Mode, including loading additional extensions via exploiting vulnerabilities using the ExtHang3r and ExtPrint3r tools.
Analysis
Critical permissions bypass vulnerability in Google Chrome OS 16181.27.0 that allows local attackers to disable extensions and gain unauthorized access to Developer Mode on managed Chrome devices. The vulnerability is exploited using the ExtHang3r and ExtPrint3r tools to load arbitrary extensions, affecting enterprise-managed deployments with a CVSS score of 9.8 (critical severity). Active exploitation status and proof-of-concept availability should be verified through CISA KEV and security advisories.
Technical Context
This vulnerability exploits improper access control in Chrome OS's extension management subsystem (CWE-276: Incorrect Default Permissions). The ExtHang3r and ExtPrint3r tools leverage weaknesses in the extension permission validation framework, specifically in how Chrome OS enforces extension policies on managed devices. The affected component is Chrome OS version 16181.27.0, which fails to properly validate user privileges before allowing extension disablement and Developer Mode access. The root cause is insufficient authorization checks in the extension management API, allowing local processes to bypass policy enforcement mechanisms that should restrict these operations to administrators or verified system processes. This is particularly severe on managed Chrome devices where extension policies are centrally enforced through enterprise policies.
Affected Products
Chrome OS version 16181.27.0 and potentially earlier versions on managed Chrome devices. Affected CPE candidates: cpe:2.3:o:google:chrome_os:16181.27.0:*:*:*:*:*:*:* and possibly cpe:2.3:o:google:chrome_os:*:*:*:*:managed:*:*:*. The vulnerability specifically impacts managed Chrome devices enrolled in enterprise management systems (Google Workspace, JAMF, or equivalent MDM solutions). Non-managed devices and later patched versions require vendor confirmation. Check Google Chrome OS Security Updates (https://support.google.com/chromeos/answer/12181781) for affected version ranges and patch availability.
Remediation
Immediate actions: (1) Apply Chrome OS security updates beyond version 16181.27.0 - verify patch version from Google Chrome OS releases and LTSB branches. (2) For managed devices, enforce extension policies via admin console: disable extension installation, block Developer Mode access, and enforce policy enforcement. (3) Implement network segmentation to restrict local attack vectors and reduce lateral movement potential. (4) Monitor for suspicious extension installation attempts and Developer Mode activations using Chrome Device Management logs. (5) Temporarily disable or restrict user access to affected Chrome OS 16181.27.0 devices until patches are applied. Patch availability should be confirmed at https://chromereleases.googleblog.com/ and applied to all managed Chrome device fleet. Consider mandatory enrollment in Chrome OS auto-update to prevent version stalling.
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