CVE-2026-11092: Chrome DevTools Policy Enforcement Flaw Enables Privilege Escalation via Malicious Extension

Technical summary

CVE-2026-11092 stems from insufficient policy enforcement within Chrome's DevTools infrastructure. The vulnerability is classified as CWE-602 (Client-Side Enforcement of Server-Side Security), indicating that security controls that should prevent unauthorized actions are inadequately enforced on the client side. An attacker crafting a malicious extension can exploit this weakness to escalate from extension-level permissions to higher privilege contexts. The flaw requires social engineering to deliver the malicious extension, but once installed, no additional user interaction is needed to trigger the privilege escalation itself. Chromium has rated the security severity as Medium, though the CVSS score of 8.8 reflects the high impact potential if successfully exploited.

Business impact

Successful exploitation enables attackers to gain unauthorized access to sensitive browser data, including authentication tokens, cached credentials, and user browsing history. In enterprise environments where Chrome is the standard browser, compromised user accounts could serve as entry points for lateral movement and data exfiltration. The attack vector is practical: phishing campaigns delivering malicious extensions, bundled installers, or deceptive app store listings can achieve the initial user install. Organizations relying on extension-based security controls may find those controls bypassed by this privilege escalation.

Affected systems

Google Chrome versions prior to 149.0.7827.53 are vulnerable. The flaw affects Chrome across all major operating systems: Windows, macOS, and Linux. Any user or device running an older Chrome build is at risk if targeted with a malicious extension. Organizations with auto-update enabled will receive patches automatically, but those managing updates manually or running older ESR (Extended Stable Release) versions should prioritize verification and deployment.

Exploitability

The attack requires social engineering to convince a user to install a malicious extension. In some cases, attackers may use fake app stores, compromised websites, or phishing emails to distribute the extension. However, once the extension is installed, the privilege escalation occurs without requiring additional user action or interaction. The flaw is not known to have been exploited in the wild as of publication, and it has not been added to CISA's Known Exploited Vulnerabilities (KEV) catalog. Nevertheless, the relative ease of crafting a malicious extension and the low bar for delivery via social engineering mean defenders should not assume this will remain unexploited for long.

Remediation

Organizations should upgrade Google Chrome to version 149.0.7827.53 or later immediately. Verify the update in Chrome Settings > About Chrome, which will display the current version and auto-check for updates. For managed environments using Google Admin Console or equivalent mobile device management (MDM) tools, push the update to all endpoints. Additionally, review extension policies: disable untrusted extension stores, restrict which extensions can be installed, and educate users about the risks of installing extensions from unofficial sources.

Patch guidance

Google Chrome auto-updates by default; users should restart their browser to complete the update to version 149.0.7827.53 or later. Enterprise administrators managing Chrome via policies should consult Google's official security advisory and release notes to confirm version rollout timelines. Verify successful patching by checking Settings > About Chrome or using your organization's endpoint management tools to report on Chrome version compliance. For users unable to auto-update, manual download of the latest stable release from google.com/chrome is recommended.

Detection guidance

Monitor for extension installation activity, particularly from non-official sources. In managed environments, audit extension usage via Chrome Management Console or equivalent tools. Look for extensions installed from untrusted publishers or those with suspicious permission requests (e.g., unrestricted access to all websites or DevTools APIs). Network detection is difficult since the attack occurs within the browser process; focus on user awareness training to catch malicious installation attempts before they occur. If a suspected malicious extension has been installed, inspect the extension's ID, publisher, and permissions, then revoke its installation policy and remove it from affected devices.

Why prioritize this

Despite Chromium's Medium severity rating, the CVSS 8.8 score reflects high impact (confidentiality, integrity, and availability compromise). The attack requires user interaction but is practical and scalable via social engineering. The lack of KEV designation should not delay patching; organizations should treat this as high priority given Chrome's ubiquity in both consumer and enterprise environments. Privilege escalation flaws that bypass extension sandboxing are particularly concerning because they undermine a key security boundary.

Risk score, explained

The CVSS 8.8 HIGH score is driven by three factors: (1) network accessibility (AV:N) allows remote delivery of the malicious extension via web or phishing; (2) low attack complexity (AC:L) means no special conditions are needed once the extension is installed; (3) high impact across all three CIA dimensions (C:H/I:H/A:H) because the attacker gains privileged access to browser data and processes. The requirement for user interaction (UI:R) to install the extension prevents a maximum score, but does not substantially reduce the practical risk given social engineering effectiveness.

Frequently asked questions