CVE-2026-121101 in Chrome
Summary
by MITRE • 11/03/2026
Missing authorization in DevTools in Google Chrome prior to 157.0.8103.38 allowed a remote attacker leveraging social engineering to bypass system access restrictions into a privileged page via a crafted Chrome extension. (Chromium security severity: Low)
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Analysis
by VulDB Data Team • 11/04/2026
The vulnerability identified as missing authorization within the Google Chrome DevTools component represents a critical flaw in how browser extensions interact with privileged internal pages, specifically those accessible through developer tools. This issue stems from an insufficient access control mechanism that fails to properly validate whether a requesting extension possesses the necessary permissions or privileges before granting it access to sensitive system resources. In modern web browsers, particularly Google Chrome, DevTools serve as powerful debugging interfaces for developers, providing deep insight into page performance, network activity, and DOM structure. However, these tools also expose internal APIs that can be exploited if proper safeguards are not enforced against maliciously crafted extensions. The security severity is classified as low by the Chromium team because exploitation requires significant user interaction, yet it remains a serious concern for enterprise environments where extension management policies may be loosely configured or where users might inadvertently install untrusted add-ons.
The technical flaw lies in the authorization logic governing how Chrome extensions invoke methods within the DevTools environment. When an extension attempts to access privileged pages such as chrome://devtools/ or related internal endpoints, the browser should verify that the calling context has explicit permission defined in its manifest file and granted by the user during installation. In this case, the validation process was bypassed due to a logic error where certain API calls did not trigger the expected authorization checks. This allows an attacker who creates a malicious Chrome extension to trick users into installing it through social engineering tactics such as phishing emails or deceptive websites promising useful functionality. Once installed, the extension can programmatically interact with DevTools components without triggering standard permission warnings or restrictions that would normally block unauthorized access attempts.
The operational impact of this vulnerability centers on the potential for privilege escalation within the browser sandbox environment. Although Chrome employs a robust multi-process architecture designed to isolate web content from system resources, bypassing authorization checks in DevTools can allow an attacker to read sensitive data stored locally by other extensions or pages, manipulate debugging sessions to inject malicious code into active tabs, or potentially exfiltrate cookies and session tokens if the victim is logged into critical services. The reliance on social engineering means that direct remote exploitation over the internet without user interaction is not feasible; instead, attackers must convince a target to install the crafted extension. This shifts the attack vector from purely technical exploits to human-centric threats, making awareness training and strict extension policies vital defenses for organizations relying on Chrome as their primary browser.
Mitigation strategies primarily involve updating Google Chrome to version 157.0.8103.38 or later, where this authorization check has been corrected to ensure that all requests from extensions to privileged DevTools pages are properly validated against the extension’s declared permissions and user-granted consent levels. Administrators should also enforce strict policies regarding which extensions can be installed across managed devices using Chrome Enterprise policies, such as BlockList or AllowedList configurations, to prevent users from installing unvetted add-ons. Additionally, enabling enhanced security features like Safe Browsing for extensions and regularly auditing installed plugins can reduce the risk of social engineering success. From a broader cybersecurity framework perspective, this vulnerability aligns with CWE-269 Improper Privilege Management, as it involves failing to enforce required permissions before allowing access to protected resources. It also relates to ATT&CK technique T1059 Command and Scripting Interpreter if used for further exploitation within the browser context, highlighting the importance of monitoring extension behavior in endpoint detection systems.