CVE-2026-79203 in Chrome
Summary
by MITRE • 08/26/2026
Improper input validation in DevTools in Google Chrome prior to 152.0.7977.65 allowed a remote attacker who had compromised the renderer process to bypass site isolation via a crafted HTML page. (Chromium security severity: Medium)
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Analysis
by VulDB Data Team • 08/26/2026
The vulnerability identified as an improper input validation flaw within Google Chrome's DevTools component prior to version 152.0.7977.65 represents a significant breach in the browser's defense-in-depth architecture, specifically targeting the mechanism known as site isolation. Site isolation is a critical security feature designed to prevent cross-site data theft by ensuring that each website runs in its own unique process with isolated memory space. This architectural separation prevents malicious scripts from one origin from accessing sensitive data belonging to another origin, even if they are rendered within the same browser window or tab. The flaw arises because DevTools, which is primarily intended for developers and debugging purposes, failed to adequately sanitize inputs when interacting with renderer processes that may have been compromised by an attacker.
From a technical perspective, this vulnerability falls under CWE-20: Improper Input Validation, as the software did not sufficiently verify or sanitize user-supplied input before processing it within privileged contexts. When a remote attacker successfully compromises a renderer process through other means such as exploiting a separate memory corruption bug or executing malicious JavaScript in an untrusted context, they can leverage this DevTools flaw to escalate their privileges and break out of the sandboxed environment. By crafting a specific HTML page that triggers the validation failure, the attacker can manipulate internal state variables or command structures within DevTools to execute actions outside the intended scope of the renderer process. This effectively allows the attacker to bypass site isolation protections, granting them access to data from other sites that should remain strictly isolated due to same-origin policy constraints.
The operational impact of this vulnerability is severe because it undermines one of Chrome's most effective mitigations against cross-site scripting and data exfiltration attacks. If an attacker can bypass site isolation, they may be able to read cookies, local storage contents, or other sensitive user data from different domains that the victim has visited. This capability aligns with ATT&CK technique T1059: Command and Scripting Interpreter, as it involves using browser-based scripting mechanisms to achieve unauthorized access, and potentially T1074: Data Staged for Exfiltration if the attacker uses this access to gather data before sending it out of the network. The Chromium security severity rating of Medium reflects that while exploitation requires a pre-existing compromise of the renderer process, the resulting privilege escalation significantly increases the blast radius of an initial breach.
Mitigation strategies primarily involve updating Google Chrome to version 152.0.7977.65 or later where this input validation logic has been corrected and hardened. For organizations managing large fleets of devices, deploying automated patch management systems is essential to ensure timely application of these security updates. Additionally, administrators should consider restricting the use of DevTools in production environments by disabling developer tools via command-line flags for standard user accounts, thereby reducing the attack surface available to potential adversaries who might attempt to leverage this specific component. Regular auditing of browser configurations and enforcing strict content security policies can further limit the ability of malicious scripts to interact with debugging interfaces that could be abused for such bypasses.