CVE-2026-78941 in Chrome
Summary
by MITRE • 08/26/2026
Information leak in Core 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 information leak within the core components of Google Chrome prior to version 152.0.7977.65 represents a significant breach in browser security architecture, specifically targeting the integrity of site isolation mechanisms. Site isolation is a critical defense strategy employed by modern web browsers to prevent cross-site scripting and data theft attacks by ensuring that pages from different origins are rendered in separate processes with isolated memory spaces. This architectural separation prevents malicious scripts running on one website from accessing sensitive data belonging to another, such as cookies or local storage contents, even if the user is logged into both sites simultaneously. The flaw described indicates a failure in this isolation boundary, allowing a remote attacker who has already achieved code execution within a renderer process to bypass these protections and access memory or state information intended for other origins.
From a technical perspective, this vulnerability falls under the category of improper restriction of operations within the bounds of a memory buffer or context, often classified under CWE-200: Information Exposure. The specific mechanism likely involves an incorrect handling of inter-process communication or shared resources where sensitive data is inadvertently exposed to processes that should not have access to it. When a renderer process is compromised, typically through a successful cross-site scripting attack or exploitation of another vulnerability in web content, the attacker gains limited execution privileges within that sandboxed environment. However, due to this information leak flaw, the attacker can leverage crafted HTML pages to probe and extract data from other isolated contexts. This bypasses the fundamental assumption that renderer processes are strictly confined to their assigned origin's scope, effectively collapsing the security perimeter designed by Chromium developers.
The operational impact of this vulnerability is severe for users who engage in multi-account browsing or access sensitive web applications such as online banking, email services, and enterprise portals within the same browser instance. By bypassing site isolation, an attacker can potentially steal session tokens, authentication cookies, or other confidential data stored by legitimate websites. This capability transforms a relatively contained renderer compromise into a broader security incident where the confidentiality of user data across multiple sites is compromised. The Chromium project has assigned this issue a medium severity rating, reflecting its potential for exploitation in targeted attacks rather than widespread automated abuse, yet it remains critical because site isolation bypasses are often used as stepping stones for more advanced persistent threats or large-scale credential harvesting campaigns.
Mitigation strategies primarily involve immediate software updates to ensure that all instances of Google Chrome and Chromium-based browsers are upgraded to version 152.0.7977.65 or later, where the underlying flaw in the core has been patched. For organizations managing fleets of devices, deploying automated patch management systems is essential to minimize the window of exposure. Additionally, users should be advised to utilize separate browser profiles for different levels of trust when accessing sensitive accounts, providing an additional layer of isolation independent of technical controls. Security monitoring tools that detect anomalous behavior in renderer processes or unusual memory access patterns can also help identify potential exploitation attempts before significant data exfiltration occurs. This incident underscores the continuous arms race between browser developers and attackers, highlighting the importance of maintaining strict adherence to security standards such as those outlined in the MITRE ATT&CK framework under techniques related to credential harvesting and bypassing process isolation mechanisms.