CVE-2026-121203 in Chrome
Summary
by MITRE • 11/03/2026
Use after free in Geometry in Google Chrome prior to 157.0.8103.38 allowed a remote attacker to execute arbitrary code inside the sandbox via a crafted HTML page. (Chromium security severity: Critical)
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Analysis
by VulDB Data Team • 11/03/2026
The vulnerability identified as a use-after-free error within the Geometry component of Google Chrome prior to version 157.0.8103.38 represents a critical memory corruption flaw that undermines the browser's core security model. This specific defect occurs when the application continues to reference a memory block after it has been freed, leading to undefined behavior during rendering operations involving geometric calculations. The root cause lies in improper management of object lifecycles within the graphics processing pipeline, where pointers are not nullified or invalidated immediately upon deallocation. Consequently, subsequent access to these dangling pointers can result in arbitrary read and write capabilities within the context of the renderer process. This flaw is particularly dangerous because it allows an attacker to manipulate memory structures that control execution flow, potentially leading to code injection techniques such as return-oriented programming or direct shellcode execution.
From a technical perspective, this vulnerability aligns with CWE-416, which classifies use-after-free errors as a significant category of software weaknesses related to improper resource management. The exploitation vector involves crafting an HTML page that triggers specific geometric rendering operations within the browser's engine. When the victim visits this malicious webpage, the attacker-controlled input causes the geometry module to free memory associated with certain graphical objects while retaining references to them elsewhere in the application state. By carefully timing subsequent interactions with these freed objects, a remote attacker can achieve arbitrary code execution inside the sandboxed renderer process. Although Chrome employs multiple layers of defense including ASLR and DEP, successful exploitation of this flaw allows bypassing some of these mitigations by leveraging memory corruption to hijack control flow or leak sensitive data from adjacent memory regions.
The operational impact of this vulnerability is severe due to its potential for remote code execution without user interaction beyond visiting a webpage. The Chromium security severity rating of Critical reflects the high likelihood of successful exploitation and the significant consequences thereof, including full compromise of the browser session and potentially the underlying operating system if sandbox escape techniques are combined with this initial foothold. Attackers can leverage this flaw to install malware, steal credentials, or establish persistent access on affected systems. The presence of such a vulnerability in core rendering components highlights the complexity inherent in modern web browsers and the critical importance of rigorous memory safety practices in their development lifecycle.
Mitigation strategies primarily involve updating Google Chrome to version 157.0.8103.38 or later, where these memory management issues have been addressed through improved pointer handling and stricter validation checks before dereferencing objects. For organizations unable to patch immediately, deploying network-level controls such as web filtering proxies can help block access to known malicious domains hosting exploit kits that target this specific vulnerability. Additionally, enabling Chrome's sandboxing features ensures that even if exploitation occurs, the damage is contained within a restricted environment rather than affecting the entire system. Security teams should also monitor for indicators of compromise associated with browser-based attacks and ensure that endpoint detection systems are configured to detect unusual memory access patterns indicative of use-after-free exploits. This incident underscores the necessity of maintaining up-to-date software versions and adhering to secure coding standards like those outlined in CWE-416 to prevent similar vulnerabilities in future releases.