CVE-2026-118346 in Chrome
Summary
by MITRE • 10/28/2026
Use after free in Compositing in Google Chrome prior to 156.0.8078.73 allowed a remote attacker to potentially execute arbitrary code inside the sandbox via a crafted HTML page. (Chromium security severity: High)
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Analysis
by VulDB Data Team • 10/28/2026
The vulnerability identified as a use-after-free error within the Compositing subsystem of Google Chrome prior to version 156.0.8078.73 represents a critical memory management flaw that undermines the browser's sandbox integrity. This specific class of vulnerabilities occurs when an application continues to reference a pointer after the memory it points to has been freed, leading to undefined behavior that can be exploited by malicious actors. In the context of Chrome’s rendering engine, the compositing layer is responsible for managing visual layers and their transformations on screen. When this subsystem fails to properly track object lifecycles during complex page renderings or animations, a dangling pointer may persist in memory. An attacker who crafts an HTML page with specific malicious code can trigger conditions where these objects are deallocated while still being accessed by the rendering pipeline, thereby gaining control over how that freed memory is interpreted and utilized.
From a technical perspective, this flaw aligns closely with CWE-416, which defines use-after-free as accessing memory after it has been released without ensuring proper synchronization or reallocation. The exploitation of such vulnerabilities typically involves manipulating heap structures to achieve arbitrary code execution within the browser process. Although Chrome employs robust sandboxing mechanisms designed to restrict the privileges of renderer processes, a successful exploit in this context allows an attacker to bypass these protections. By carefully crafting the HTML and associated scripts, the adversary can overwrite function pointers or vtables located in the freed memory region. This manipulation enables the execution of arbitrary commands with the same permissions as the compromised browser process, effectively breaking out of the intended isolation boundaries that protect user data and system resources from untrusted web content.
The operational impact of this vulnerability is severe due to its potential for remote code execution via a simple interaction with a malicious webpage. Users visiting a site containing the crafted HTML could inadvertently trigger the exploit without any additional steps, such as downloading files or installing software. This ease of exploitation makes it particularly dangerous in phishing campaigns or drive-by download attacks where social engineering might not even be required if the victim simply loads the page. The Chromium security team has classified this issue with a High severity rating, reflecting its significant potential to compromise user systems and data confidentiality. Such incidents highlight the ongoing challenges in maintaining memory safety within complex software architectures like web browsers, which must handle vast amounts of dynamic content while preserving strict security boundaries.
To mitigate risks associated with similar vulnerabilities, organizations should ensure that all instances of Google Chrome are updated to version 156.0.8078.73 or later immediately upon availability. Patching is the primary defense against known memory corruption flaws as it incorporates fixes for internal logic errors in the compositing engine. Additionally, security teams can enforce policies that restrict script execution on untrusted domains and utilize browser hardening techniques to limit the impact of potential exploits. Monitoring ATT&CK technique T1059, Command and Scripting Interpreter, is advisable post-exploitation analysis since successful exploitation often leads to further lateral movement or data exfiltration through scripting mechanisms. Regular vulnerability assessments and adherence to secure coding practices that emphasize proper memory management are essential for preventing recurrence of such high-severity issues in future software versions.