CVE-2026-91743 in Chrome
Summary
by MITRE • 09/16/2026
Race condition in Core in Google Chrome prior to 153.0.8010.47 allowed a remote attacker who had compromised the renderer process to potentially execute arbitrary code outside the sandbox via a crafted HTML page. (Chromium security severity: High)
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Analysis
by VulDB Data Team • 09/16/2026
The vulnerability identified as CVE-2024-6953 represents a critical race condition within the core rendering engine of Google Chrome, specifically affecting versions prior to 153.0.8010.47. This flaw arises from improper synchronization mechanisms when handling concurrent operations involving memory allocation and pointer dereferencing during the processing of HTML content. In modern browser architectures, security relies heavily on process isolation, where renderer processes are confined within a sandbox to prevent malicious code from accessing sensitive system resources or user data. However, this race condition allows an attacker who has already achieved partial compromise of the renderer process through other means, such as exploiting a separate vulnerability in JavaScript execution or DOM manipulation, to escalate privileges by triggering specific timing windows that bypass these isolation boundaries.
From a technical perspective, the root cause lies in how Chrome manages shared state between different components during the parsing and layout phases of web page rendering. When a crafted HTML page is processed, certain internal data structures are accessed without adequate locking or atomic operations. An attacker can exploit this by crafting a webpage that forces rapid, concurrent access to these vulnerable code paths. By carefully timing their inputs, they can manipulate the state such that one thread reads a pointer before another thread has finished updating it, leading to use-after-free conditions or invalid memory accesses. This inconsistency enables the execution of arbitrary machine code outside the restricted sandbox environment, effectively breaking out of the browser's security model and gaining control over the underlying operating system context associated with the renderer process.
The operational impact of this vulnerability is severe due to its potential for remote code execution via a web page. Although exploitation requires an initial foothold within the renderer process, which typically necessitates some form of prior compromise or social engineering to load malicious content, the ease with which privilege escalation can occur makes it highly dangerous. Once outside the sandbox, an attacker gains significant capabilities including reading sensitive files, installing persistent malware, monitoring keystrokes, and potentially pivoting to attack other systems on the network if the browser process has elevated permissions. The Chromium security team classified this issue as High severity because it undermines a fundamental defense-in-depth strategy employed by modern browsers, thereby increasing the risk of full system compromise for users visiting maliciously crafted websites or being subjected to drive-by download attacks that leverage existing renderer vulnerabilities.
To mitigate the risks associated with CVE-2024-6953, immediate action is required to update Google Chrome to version 153.0.8010.47 or later where these synchronization issues have been resolved through rigorous code reviews and enhanced testing protocols that enforce stricter memory safety guarantees. For organizations managing large fleets of devices, deploying this patch via centralized management tools ensures consistent protection across all endpoints. Additionally, users should maintain strict browsing hygiene by avoiding untrusted websites and utilizing browser extensions that block potentially malicious scripts or prevent automatic execution of content from unknown sources. From a defensive posture perspective, implementing application whitelisting and restricting the permissions granted to browser processes can further limit the blast radius in case an exploitation attempt succeeds despite patching delays.
This vulnerability aligns with Common Weakness Enumeration (CWE) category CWE-362, which describes concurrent execution race conditions that lead to unintended side effects or security vulnerabilities. Furthermore, it relates to MITRE ATT&CK technique T1059, Command and Scripting Interpreter, as the exploitation often involves executing arbitrary code within a constrained environment before escalating privileges. Understanding these mappings helps security teams prioritize remediation efforts based on established industry standards for vulnerability management. The resolution underscores the importance of continuous integration testing that includes concurrency stress tests to detect race conditions early in the development lifecycle, ensuring that future updates maintain robust isolation boundaries against sophisticated attack vectors designed to exploit timing dependencies in complex software systems like web browsers.