CVE-2026-121189 in Chrome
Summary
by MITRE • 11/03/2026
Use after free in Browser in Google Chrome prior to 157.0.8103.38 allowed a remote attacker to execute arbitrary code outside the sandbox via a crafted HTML page. (Chromium security severity: Low)
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Analysis
by VulDB Data Team • 11/03/2026
The vulnerability identified as a use-after-free condition within the browser component of Google Chrome prior to version 157.0.8103.38 represents a critical memory management error that compromises the integrity and confidentiality of user data. This flaw arises when the application continues to reference a memory block after it has been freed, leading to undefined behavior that can be exploited by malicious actors. In the context of web browsers, such vulnerabilities are particularly dangerous because they occur in high-privilege processes or sandboxed environments where strict isolation is required to prevent code execution from untrusted sources. The specific classification as a low severity issue within Chromium suggests that while the vulnerability exists and is technically exploitable under certain conditions, it may require precise timing or complex exploitation techniques to achieve arbitrary code execution outside of the browser's security sandbox.
From a technical perspective, use-after-free vulnerabilities typically occur when an object is deallocated but pointers to that memory remain valid in other parts of the program. When the attacker crafts a specific HTML page containing malicious JavaScript or embedded content, they can trigger the premature freeing of a critical data structure while retaining references to it. By manipulating these dangling pointers, an attacker can overwrite adjacent memory structures with controlled values. This manipulation allows for arbitrary read and write operations within the browser process space. If successful, this leads to code execution privileges that bypass the sandbox boundaries designed to isolate web content from the underlying operating system. The exploitation chain likely involves leveraging specific rendering engine features or JavaScript garbage collection behaviors to control the allocation of new objects into the freed memory region, thereby gaining control over program flow and executing arbitrary commands on the victim's machine.
The operational impact of this vulnerability is significant despite its low severity rating in internal tracking systems. A successful exploit could allow a remote attacker to execute arbitrary code outside the sandbox, effectively compromising the user's system integrity. This means that visiting a malicious website or clicking a crafted link could result in malware installation, data theft, or further lateral movement within a network if the browser is used as an entry point. The ability to escape the sandbox is particularly concerning because modern browsers rely heavily on this isolation mechanism to protect users from web-based attacks. Even though the severity is rated low, indicating potential difficulties in reliable exploitation, any successful breach undermines trust in the browser's security model and exposes users to severe risks including credential harvesting, session hijacking, or full system compromise depending on the user's privileges.
Mitigation strategies primarily involve updating Google Chrome to version 157.0.8103.38 or later, which includes patches for this memory management flaw. Users should ensure automatic updates are enabled to receive security fixes promptly. For organizations managing multiple endpoints, centralized patch management systems should be configured to deploy these updates across all affected devices without delay. Additionally, users can reduce their exposure by employing browser hardening techniques such as disabling unnecessary plugins or scripts, using content security policies where applicable, and avoiding interaction with untrusted web content until the update is applied. Security teams should also monitor for indicators of compromise related to this vulnerability in network traffic logs and endpoint detection systems to identify any potential exploitation attempts before they result in a full breach.
This incident aligns with common weakness enumeration standards such as CWE-416, which describes use after free errors resulting from improper memory management practices during software development. The attack vector corresponds to ATT&CK technique T1059, specifically command and script interpretation via JavaScript or similar scripting engines used in web browsers. Understanding these mappings helps security professionals categorize the risk accurately within broader threat intelligence frameworks and prioritize remediation efforts based on industry-standard classifications of vulnerability severity and exploitability.