CVE-2026-118357 in Chrome
Summary
by MITRE • 10/28/2026
Use after free in FileSystem 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 condition within the FileSystem component of Google Chrome prior to version 156.0.8078.73 represents a critical memory management flaw that undermines the browser's integrity and isolation mechanisms. This specific class of error occurs 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 this context, the FileSystem API is responsible for managing access to local file systems from web applications, making it a high-value target for attackers seeking to bypass security boundaries. The presence of such a flaw indicates a failure in proper reference counting or lifecycle management within the Chromium rendering engine's handling of filesystem objects.
From a technical perspective, this vulnerability allows a remote attacker to potentially execute arbitrary code inside the browser sandbox by crafting a malicious HTML page that triggers the premature deallocation of memory while active references remain. When the freed memory is subsequently accessed, it may point to stale data or be reallocated for other purposes, allowing an attacker to manipulate program flow and achieve code execution within the restricted environment of the renderer process. Although Chrome employs sandboxing techniques designed to limit the impact of such exploits by restricting access to system resources, a successful exploitation could still lead to privilege escalation if additional vulnerabilities are chained together or if the sandbox boundaries are breached through side-channel attacks or other advanced techniques.
The operational impact of this vulnerability is significant due to its potential for remote code execution via standard web interactions. An attacker only needs to host a crafted HTML page and lure a user with an outdated version of Chrome prior to 156.0.8078.73 into visiting it. Once executed, the malicious script could compromise the user's browsing session, steal sensitive data such as cookies or credentials stored in memory, or serve as a foothold for further attacks against the underlying operating system if sandbox escape techniques are employed. This risk is exacerbated by the widespread use of Chrome and its derivatives across enterprise environments where automated updates may not be immediately enforced on all endpoints.
To mitigate this risk, organizations must ensure that Google Chrome is updated to version 156.0.8078.73 or later as soon as possible. This update contains patches for the memory management issues within the FileSystem component that prevent the use-after-free condition from being triggered. Additionally, administrators should enforce strict software update policies across all user devices to minimize exposure to known vulnerabilities in web browsers. Security teams should also monitor for indicators of compromise related to browser-based exploits and consider implementing application whitelisting or sandboxing solutions at the endpoint level to provide defense-in-depth against potential exploitation attempts that might bypass patch delays.
This vulnerability aligns with Common Weakness Enumeration identifier CWE-416, which describes use after free errors resulting from improper memory management practices in software development. In terms of attack tactics and techniques, this exploit vector corresponds to MITRE ATT&CK technique T1203, specifically the exploitation phase where attackers leverage vulnerabilities in applications to execute code on target systems. Understanding these mappings helps security professionals prioritize remediation efforts based on established industry standards for vulnerability classification and threat modeling.