CVE-2026-113040 in Chrome
Summary
by MITRE • 10/21/2026
Improper input validation in Proxy in Google Chrome prior to 156.0.8078.47 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 • 10/21/2026
The vulnerability identified as an improper input validation flaw within the Proxy component of Google Chrome prior to version 156.0.8078.47 represents a significant breach in browser security boundaries. This defect allows a remote attacker, through the delivery of a specially crafted HTML page, to bypass standard sandboxing mechanisms and potentially execute arbitrary code with elevated privileges inside the restricted environment. The core technical issue stems from insufficient sanitization or type checking of data inputs processed by the proxy subsystem, which is responsible for managing network requests and routing traffic between the browser engine and external servers. When a user visits a maliciously constructed webpage containing specific malformed payloads, the browser fails to correctly validate these inputs before passing them to lower-level system calls or internal handlers. This lack of rigorous validation creates an entry point where attacker-controlled data can be interpreted as executable instructions rather than passive content, leading to code execution within the sandboxed process context.
From a technical perspective, this vulnerability aligns with Common Weakness Enumeration (CWE) categories such as CWE-20 Improper Input Validation and potentially CWE-94 Code Injection if the flaw allows for direct injection of malicious scripts or binary data into executable contexts. The severity is classified as High by Chromium security standards because it undermines one of the most critical defense-in-depth layers in modern web browsers: the sandbox. Browsers rely heavily on isolating different tabs, plugins, and network operations to prevent a compromise in one area from affecting the entire system or other user data. By exploiting this input validation gap, an attacker can escape these isolation boundaries, effectively gaining control over processes that should remain restricted. This capability transforms what might otherwise be a cross-site scripting issue into a full remote code execution vulnerability, significantly increasing the potential impact of the exploit.
The operational impact of this flaw is severe for end-users and enterprise environments alike. A successful exploitation could allow an attacker to install malware, steal sensitive credentials stored in browser memory or cookies, monitor user activity, or use the compromised machine as part of a botnet. Since the attack vector involves simply visiting a crafted HTML page, it falls under the category of drive-by attacks where no additional interaction from the victim is required beyond loading the malicious content. This makes the vulnerability particularly dangerous in scenarios involving phishing campaigns, compromised advertising networks, or malicious websites that users might be directed to via social engineering tactics. The ability to execute code inside the sandbox means that even if the browser prevents direct access to the operating system kernel, the attacker can still manipulate local files, exfiltrate data from other tabs, and establish persistence mechanisms within the user profile directory.
To mitigate this risk, immediate action is required to update Google Chrome to version 156.0.8078.47 or later, where these input validation checks have been hardened. Organizations should enforce automatic updates for all browser installations to ensure that security patches are applied promptly upon release. Additionally, implementing strict content security policies and restricting the execution of untrusted scripts can provide an additional layer of defense against similar exploitation attempts. Security teams should also monitor network traffic for unusual outbound connections or suspicious process behaviors that might indicate a successful compromise via this vector. Regular vulnerability scanning and patch management cycles are essential to maintain resilience against such high-severity browser vulnerabilities, ensuring that the attack surface is minimized before attackers can leverage known flaws in widespread software deployments.