CVE-2026-106301 in Chrome
Summary
by MITRE • 10/06/2026
Confused deputy in Contextual Tasks in Google Chrome prior to 155.0.8059.39 allowed a remote attacker who had compromised the renderer process to bypass system access restrictions into a privileged page via a crafted HTML page. (Chromium security severity: Medium)
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Analysis
by VulDB Data Team • 10/07/2026
The vulnerability identified as a confused deputy issue within Google Chrome prior to version 155.0.8059.39 represents a significant breach in the browser's process isolation model, specifically affecting contextual tasks and privileged page access mechanisms. This flaw allows an attacker who has already achieved code execution or compromise of a renderer process to escalate privileges by bypassing system-level access restrictions. The core technical failure lies in the improper handling of context when performing operations that require elevated permissions. In modern browser architectures like Chromium, different processes handle distinct security contexts such as normal web pages, extensions, and privileged internal pages. A confused deputy vulnerability occurs when a trusted process or component is tricked into performing an action on behalf of an untrusted entity without properly verifying the identity or intent of that entity. In this specific instance, the renderer process, which should be sandboxed to prevent access to sensitive system resources, was able to exploit a logic error in how contextual tasks were processed. By crafting a malicious HTML page, an attacker could manipulate these tasks to execute operations within a privileged context, effectively tricking the browser into granting unauthorized access that violates the principle of least privilege.
From a technical perspective, this vulnerability exploits weaknesses in the boundary checks between renderer processes and higher-privilege components such as the browser process or service workers. The Chromium security team classified this issue with medium severity because while it requires an initial compromise of the renderer, successful exploitation leads to a broader breach of the sandbox environment. This is particularly dangerous because renderer compromises are often achievable through standard web-based attacks like cross-site scripting or drive-by downloads. Once inside the renderer, the attacker leverages the confused deputy flaw to interact with APIs or interfaces that should be restricted to trusted contexts only. The attack vector involves delivering a crafted HTML page that triggers specific contextual task handlers within Chrome. These handlers fail to adequately validate whether the request originates from an authorized source or adheres to expected security constraints. Consequently, the browser executes actions in a privileged state as if they were initiated by legitimate system components, allowing the attacker to read sensitive data, modify protected settings, or potentially pivot further into the host operating system depending on the specific privileges granted during the bypass.
The operational impact of this vulnerability is substantial for users relying on Chrome for secure browsing and enterprise environments where strict sandboxing policies are enforced. An attacker who successfully exploits this flaw can access information that was intended to be isolated from web content, such as cookies, local storage data associated with privileged origins, or internal browser configurations. This undermines the fundamental security guarantee of the multi-process architecture, which is designed to contain damage within a single compromised renderer. The ability to bypass these restrictions means that even if an attacker only gains initial access through a standard website visit, they can elevate their capabilities significantly without needing additional exploits targeting other components like the GPU process or network stack. This increases the risk of data exfiltration and persistent compromise, as the attacker now operates with higher privileges within the browser's ecosystem.
To mitigate this vulnerability, users must update Google Chrome to version 155.0.8059.39 or later immediately upon availability. The patch addresses the logic errors in contextual task handling by enforcing stricter validation checks before granting access to privileged interfaces. For organizations deploying Chrome at scale, it is critical to ensure that automatic updates are enabled for all endpoints to minimize the window of exposure. Additionally, security teams should monitor for indicators of compromise related to renderer process anomalies and enforce strict content security policies on internal web applications to reduce the attack surface available to potential exploiters. This incident highlights the importance of rigorous code review practices focused on inter-process communication boundaries and context validation within complex software systems like browsers.
This vulnerability aligns with CWE-274, which describes improper enforcement of a privileged operation in an unprivileged context, commonly known as a confused deputy attack. It also relates to ATT&CK technique T1059, Command and Scripting Interpreter, specifically when used for privilege escalation within application environments. The exploitation path demonstrates how logical flaws in access control mechanisms can negate the benefits of technical controls like sandboxing. By addressing these contextual validation gaps, developers reinforce the defense-in-depth strategy that protects users from escalating threats originating from compromised web content.