CVE-2026-118356 in Chrome
Summary
by MITRE • 10/28/2026
Use after free in WTF in Google Chrome prior to 156.0.8078.73 allowed a remote attacker to 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 WebKit rendering engine, commonly referred to as WTF in Google Chrome prior to version 156.0.8078.73, represents a critical memory corruption flaw that undermines the browser's security model. This specific defect arises when an object is deallocated from memory but continues to be referenced by other parts of the application logic. In the context of web browsers, this typically occurs during complex rendering operations where DOM elements or style objects are manipulated dynamically through JavaScript and CSS. When a script removes or modifies these elements, the underlying C++ code may fail to properly nullify pointers or update references before freeing the memory associated with those objects. Consequently, subsequent access to these dangling pointers results in undefined behavior, which an attacker can carefully orchestrate to achieve arbitrary code execution within the browser's sandboxed environment.
From a technical perspective, use-after-free vulnerabilities are particularly dangerous because they allow attackers to control the contents of freed memory blocks through heap spraying techniques or by allocating new objects at the same memory addresses previously occupied by the vulnerable object. By crafting a malicious HTML page that triggers this specific sequence of events in WebKit, an attacker can manipulate the state of the browser's internal data structures. This manipulation enables the overwriting of function pointers or virtual table entries with controlled values. When the browser subsequently attempts to invoke these corrupted references, it executes arbitrary machine code supplied by the attacker rather than performing legitimate operations. The severity is classified as high because this flaw bypasses standard memory safety protections and provides a direct path for remote code execution without requiring user interaction beyond visiting the crafted webpage.
The operational impact of this vulnerability extends far beyond simple data leakage or denial of service. Since Google Chrome employs a multi-process architecture with strict sandboxing to limit the damage caused by exploits, achieving arbitrary code execution inside the sandbox is a significant milestone for an attacker. While the sandbox restricts access to sensitive system resources, successfully exploiting this use-after-free flaw allows the malicious payload to operate within that restricted context. This can lead to further privilege escalation attacks where the compromised process interacts with less protected processes or escapes the sandbox entirely through secondary vulnerabilities. The ability to execute arbitrary code means an attacker could install malware, steal credentials, monitor user activity, or pivot into internal network resources depending on the browser's configuration and the presence of additional exploit chains.
This vulnerability aligns closely with Common Weakness Enumeration identifier CWE-416, which describes use after free errors where a pointer is used after its memory has been freed. In terms of offensive security frameworks, this exploitation technique maps to MITRE ATT&CK techniques related to initial access and execution via web browsers, specifically leveraging client-side code injection or crafted media content. The attack vector is classified as remote because it requires no physical access or prior authentication; a user simply needs to load the malicious HTML page in an affected version of Chrome. This ease of exploitation makes such vulnerabilities high-priority targets for threat actors deploying drive-by download attacks on compromised websites or through phishing campaigns that direct victims to specially crafted URLs designed to trigger the WebKit rendering engine flaw.
Mitigation strategies primarily involve updating Google Chrome to version 156.0.8078.73 or later, where these memory management issues in the WTF library have been addressed by developers who implemented stricter pointer validation and lifecycle management for DOM objects. For organizations unable to patch immediately, deploying browser isolation solutions can help mitigate risk by rendering web content in a remote container separate from the user's local machine. Additionally, enabling strict Content Security Policy headers on websites served internally or externally can reduce the attack surface by restricting the execution of inline scripts that might be used to trigger such vulnerabilities. Regular security audits and static analysis tools focused on C++ memory safety issues are also recommended for developers maintaining browser components to prevent similar defects in future releases.