CVE-2026-76023 in Chrome
Summary
by MITRE • 08/21/2026
Improper resource control in Linux Toolkit Theming in Google Chrome prior to 151.0.7922.173 allowed a remote attacker who had compromised the renderer process to execute arbitrary code outside the sandbox via a crafted HTML page. (Chromium security severity: High)
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Analysis
by VulDB Data Team • 08/24/2026
The vulnerability identified as an improper resource control issue within the Linux Toolkit Theming component of Google Chrome prior to version 151.0.7922.173 represents a significant breach in the browser's sandbox isolation model. This flaw specifically affects the rendering engine when processing user interface elements on Linux systems, where theme-related resources are managed by the operating system rather than strictly within the Chromium process boundaries. The core technical deficiency lies in how memory and resource handles associated with these theming components were allocated or referenced without sufficient validation against malicious input vectors embedded within web content. When a renderer process, which is already compromised by an attacker through other means such as cross-site scripting or drive-by downloads, attempts to interact with the toolkit theme subsystem, it can exploit this lack of strict resource control to bypass security restrictions intended to keep untrusted code confined.
From a technical perspective, this vulnerability falls under the category of Improper Resource Control (CWE-770), which occurs when software does not properly monitor or regulate the allocation and consumption of resources like memory, file handles, or network connections. In the context of browser security, renderer processes are designed to operate in a restricted environment where they cannot directly access system-level APIs or execute arbitrary code outside their sandboxed context. However, by crafting specific HTML pages that trigger malformed interactions with the Linux toolkit theming layer, an attacker can cause the renderer to perform operations that leak control flow back into higher-privileged contexts or allow for memory corruption techniques such as heap spraying or use-after-free scenarios. These conditions enable the execution of arbitrary code outside the sandbox, effectively breaking the isolation boundary that protects the user's system from malicious web content.
The operational impact of this vulnerability is severe due to its potential for remote code execution without user interaction beyond visiting a crafted website. Since the attack vector involves a renderer process compromise, it implies that an attacker could have already gained initial foothold via standard phishing or exploit kits but was previously contained within the sandbox. This flaw allows lateral movement from the low-privilege renderer environment to full system-level access on Linux distributions using Chrome. The severity is classified as High by Chromium security standards because it undermines one of the primary defense-in-depth mechanisms employed by modern browsers, potentially leading to complete system compromise including data theft, installation of persistent malware, or use of the device in botnets.
Mitigation strategies primarily involve updating Google Chrome to version 151.0.7922.173 or later, where patches have been applied to enforce stricter resource validation and isolation boundaries for toolkit theming operations on Linux platforms. Organizations should ensure automated update policies are active to minimize exposure windows. Additionally, defense-in-depth measures such as enabling sandbox hardening features, utilizing content security policies to restrict script execution, and monitoring renderer process behavior can provide supplementary protection against exploitation attempts while updates are being deployed. Security teams should also remain vigilant for indicators of compromise related to unusual resource consumption patterns in browser processes, which may signal active exploitation attempts targeting this class of vulnerabilities. This incident underscores the critical importance of maintaining strict separation between untrusted web content and system-level UI components across all supported operating systems within the Chromium ecosystem.