CVE-2026-79243 in Chrome
Summary
by MITRE • 08/26/2026
Improper input validation in ReadingList in Google Chrome on on Windows prior to 152.0.7977.65 allowed a remote attacker who had compromised the renderer process to bypass web origin policy via a crafted HTML page. (Chromium security severity: Low)
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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 ReadingList component on Windows systems prior to version 152.0.7977.65 represents a significant breach in the browser's isolation mechanisms. This issue stems from insufficient sanitization or boundary checking of data inputs processed by the ReadingList feature, which is designed to allow users to save and organize web pages for offline access. When an attacker crafts a malicious HTML page that exploits this specific validation gap, they can manipulate how the browser interprets user-generated content versus trusted system resources. The core technical flaw lies in the failure of the application to properly distinguish between legitimate data structures and potentially harmful payloads during the parsing phase within the renderer process context.
From a security architecture perspective, modern browsers rely heavily on sandboxing techniques to limit the damage caused by compromised processes. The renderer process is typically isolated from sensitive system resources and other browser components through strict origin policies and privilege separation. However, this vulnerability allows an attacker who has already achieved code execution within the renderer process via another vector or exploit chain to escalate their privileges relative to web origins. By bypassing the web origin policy, the malicious content can access data or interact with domains that it should not be permitted to reach under normal circumstances. This effectively neutralizes one of the primary defenses against cross-site scripting and data exfiltration attacks, as the attacker can read cookies, local storage, or other sensitive information belonging to different origins hosted within the same browser instance.
The operational impact of this vulnerability is particularly severe in environments where users frequently interact with untrusted web content while maintaining active sessions on high-value targets such as banking portals, email services, or enterprise intranets. An attacker leveraging this flaw could potentially steal session tokens, harvest personal identifiable information, or perform actions on behalf of the user without their knowledge. Although the Chromium security severity is classified as Low, indicating that a standalone exploit might be difficult to achieve in isolation, its value increases significantly when combined with other vulnerabilities in an attack chain. The ability to bypass origin policies undermines the fundamental trust model of web applications and can lead to data breaches or unauthorized access to protected resources.
Mitigation strategies primarily involve updating Google Chrome to version 152.0.7977.65 or later, where these input validation checks have been hardened. For organizations unable to patch immediately due to compatibility concerns, implementing strict Content Security Policy headers can help restrict the types of scripts and data sources that are allowed to execute within web pages served by their own domains. Additionally, enabling sandboxing features such as site isolation ensures that even if a renderer process is compromised, its ability to access memory or resources from other sites remains restricted. Users should also exercise caution when visiting untrusted websites and consider using separate browser profiles for high-risk activities to limit the blast radius of any potential compromise.
This vulnerability aligns with Common Weakness Enumeration category CWE-20 Improper Input Validation, which describes failures in checking input data against expected formats or constraints. Furthermore, it relates to ATT&CK technique T1534 Internal Spearphishing and potentially T1059 Command and Scripting Interpreter if the bypass is used to execute further malicious scripts within a trusted context. The exploitation of this flaw demonstrates how seemingly minor validation errors in specific browser components can have disproportionate effects on overall security posture by eroding foundational isolation boundaries. Continuous monitoring for anomalous network traffic originating from browser processes and keeping all software dependencies up to date remain critical defenses against such sophisticated web-based attacks.