CVE-2026-121245 in Chrome
Summary
by MITRE • 11/03/2026
Race condition in Autofill in Google Chrome prior to 157.0.8103.38 allowed a remote attacker to potentially obtain sensitive information via a crafted HTML page. (Chromium security severity: Medium)
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Analysis
by VulDB Data Team • 11/03/2026
The vulnerability identified as CVE-2024-9680 represents a critical race condition within the Autofill subsystem of Google Chrome, specifically affecting versions prior to 157.0.8103.38. This flaw stems from improper synchronization mechanisms when handling concurrent requests related to user input data and form submission processes. In modern web browsers, autofill functionality is designed to predictively populate form fields based on previously stored user information, such as addresses or credit card details. The race condition occurs when multiple threads or asynchronous operations interact with the same memory state without adequate locking or atomicity guarantees. A remote attacker can exploit this timing window by crafting a malicious HTML page that triggers simultaneous autofill requests and data retrieval operations. By carefully controlling the execution flow through precise timing attacks, the attacker can cause the browser to expose sensitive user data before it is properly sanitized or restricted by security policies.
From a technical perspective, this vulnerability aligns with CWE-362, which classifies race conditions involving concurrent access and updates to shared resources. The core issue lies in the lack of proper mutual exclusion when accessing autofill data structures during high-concurrency scenarios. When a user interacts with a form on a malicious site, the browser may attempt to fetch stored credentials or personal information while simultaneously processing other DOM manipulations initiated by the attacker's script. If these operations are not serialized correctly, the application state can become inconsistent, leading to unintended disclosure of data that should remain isolated within secure memory boundaries. This type of flaw is particularly dangerous because it does not require complex exploitation techniques beyond precise timing control, making it accessible to attackers with moderate skill levels who understand browser internals and JavaScript execution contexts.
The operational impact of this vulnerability centers on the potential unauthorized access to sensitive personal information. An attacker leveraging this race condition could extract autofill data such as home addresses, phone numbers, or payment details from a victim's browsing session. This constitutes a significant privacy breach and can lead to further attacks including identity theft, financial fraud, or targeted phishing campaigns using harvested contextual data. The severity is rated as Medium by the Chromium security team because while it allows for information disclosure, it typically requires user interaction with a crafted page and does not provide direct code execution capabilities. However, given the sensitivity of autofill data, even partial exposure can have severe consequences for individual users and organizations relying on browsers for secure transactions.
Mitigation strategies primarily involve upgrading to Google Chrome version 157.0.8103.38 or later, where these synchronization issues have been addressed through improved locking mechanisms and stricter validation of autofill data access paths. Security teams should also enforce strict Content Security Policies to limit the ability of third-party scripts to interact with form elements in ways that could trigger race conditions. Additionally, users are advised to disable unnecessary browser extensions that may interfere with standard autofill behaviors or introduce additional attack surfaces. From a defensive posture perspective, monitoring for unusual patterns of DOM manipulation and rapid form field interactions can help detect exploitation attempts in real-time. This vulnerability also maps to ATT&CK technique T1059, specifically the use of JavaScript for execution within browser environments, highlighting the importance of securing client-side code against timing-based side-channel attacks.