CVE-2026-106378 in Chrome
Summary
by MITRE • 10/07/2026
Privilege elevation in Sandbox in Google Chrome on on Mac prior to 155.0.8059.39 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: Medium)
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Analysis
by VulDB Data Team • 10/07/2026
The vulnerability identified in Google Chrome for macOS, specifically prior to version 155.0.8059.39, represents a critical failure in the browser's process isolation architecture known as sandbox escape or privilege elevation. This flaw allows an attacker who has already achieved code execution within a renderer process—a lower-privilege environment designed to contain malicious content—to break out of this confinement and execute arbitrary commands with higher system privileges. The attack vector is typically delivered through a crafted HTML page, which exploits the specific implementation details of how Chrome manages inter-process communication and resource allocation on macOS systems. By leveraging this flaw, an attacker can transition from a restricted sandboxed context to one that bypasses security boundaries, effectively neutralizing one of the primary defenses against web-based attacks.
From a technical perspective, this issue falls under the category of improper privilege management within isolated execution environments. The Chromium engine employs multiple layers of defense-in-depth, including site isolation and process sandboxes, to limit the damage caused by compromised pages. However, in versions preceding 155.0.8059.39, a logic error or unhandled edge case allowed specific sequences of operations to trick the browser into granting elevated permissions to code that should remain restricted. This type of vulnerability is often categorized under CWE-269: Improper Privilege Management, as it involves an actor obtaining access rights beyond what was intended for their current context. The exploitation requires a user to visit a maliciously constructed webpage, which then triggers the internal mechanisms responsible for sandbox enforcement in a way that results in unauthorized privilege escalation.
The operational impact of this vulnerability is severe because renderer process compromise is often achievable through common web-based attack vectors such as cross-site scripting or drive-by downloads. Once an attacker gains control over the renderer process, they are typically limited to actions within that specific browser tab or site context. However, by exploiting this sandbox escape flaw, the attacker can execute arbitrary code outside of these constraints. This means they could potentially access sensitive files on the user's Mac, install persistent malware, exfiltrate data from other applications running on the system, or use the compromised machine as a pivot point for further network attacks. The severity is rated as Medium by Chromium security standards because while it requires initial compromise of the renderer process, the subsequent privilege elevation significantly amplifies the potential damage and ease of exploitation compared to standard web-based vulnerabilities.
In terms of industry frameworks, this vulnerability aligns with MITRE ATT&CK techniques related to Privilege Escalation on macOS systems. Attackers often rely on such flaws to move from initial access via a browser to full system control without needing additional exploits or social engineering tactics beyond the initial visit to the malicious site. The lack of proper validation in how Chrome handles certain IPC calls or resource requests creates an avenue for this escalation, highlighting the importance of rigorous code review and fuzzing in complex software like web browsers where security boundaries are frequently tested by adversarial inputs.
To mitigate the risks associated with this vulnerability, it is imperative to update Google Chrome on macOS systems to version 155.0.8059.39 or later immediately upon availability. Users should ensure that automatic updates are enabled to receive future patches promptly. Additionally, organizations can implement application control policies and restrict browser configurations to limit the capabilities of renderer processes, although software patching remains the most effective remediation strategy for this specific flaw. Security teams should also monitor for indicators of compromise related to unusual process behavior or unexpected privilege changes in endpoint detection and response systems to identify potential exploitation attempts before full system compromise occurs.