CVE-2026-106295 in Chrome
Summary
by MITRE • 10/06/2026
Incorrect authorization in Unbounded Element in Google Chrome prior to 155.0.8059.39 allowed a remote attacker who had compromised the renderer process to spoof UI elements 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 an incorrect authorization issue within the Unbounded Element component of Google Chrome prior to version 155.0.8059.39 represents a significant breach in browser isolation and user interface integrity. This flaw specifically affects the rendering engine's handling of HTML elements, where the security model fails to properly restrict access or validate permissions for certain unbounded DOM structures. In modern web browsers like Chrome, the renderer process is designed to operate with limited privileges to prevent malicious code from affecting the rest of the system or other tabs. However, this specific authorization failure allows a compromised renderer process to bypass these restrictions under particular conditions involving crafted HTML content.
The technical root cause lies in how the browser processes unbounded elements within the Document Object Model when interacting with user interface components. Typically, browsers enforce strict boundaries between script execution and UI rendering to prevent spoofing attacks where malicious scripts mimic legitimate system dialogs or navigation bars. In this instance, the authorization logic governing these interactions was insufficiently robust, allowing a remote attacker who had already achieved code execution within the renderer process via another vulnerability or exploit chain to manipulate the presentation layer. By crafting specific HTML pages that leverage unbounded elements, an attacker can trick the browser into displaying fake UI elements that appear authentic but are controlled by malicious scripts.
The operational impact of this vulnerability is primarily centered around user interface spoofing and potential phishing attacks. An attacker could create a webpage that displays deceptive login prompts, security warnings, or navigation bars that closely resemble those from trusted sites such as banking portals or email services. Because these elements originate from the renderer process which has some level of trust within its own sandbox, users may be misled into believing they are interacting with legitimate interfaces. This can lead to credential theft, where victims unknowingly enter sensitive information into fields controlled by the attacker's script. Furthermore, such spoofing undermines user trust in the browser and can facilitate more sophisticated social engineering campaigns that rely on visual deception rather than technical exploitation alone.
From a threat intelligence perspective, this vulnerability aligns with CWE-269, which describes Improper Authorization, as it involves a failure to enforce proper access controls for UI manipulation functions. It also maps closely to MITRE ATT&CK technique T1087, Account Discovery, and more specifically the sub-technique of User Interface Spoofing often associated with phishing campaigns. The ability to spoof UI elements is a critical capability for attackers aiming to harvest credentials or bypass multi-factor authentication prompts by displaying fake verification screens. Although the Chromium security severity was rated as Medium, indicating that it requires specific preconditions such as renderer compromise, its potential for abuse in targeted attacks remains high due to the psychological impact of visual deception on end-users.
Mitigation strategies primarily involve updating Google Chrome to version 155.0.8059.39 or later, where these authorization checks have been strengthened and unbounded element handling has been corrected. Administrators should ensure that automatic updates are enabled for all endpoints running the browser to minimize exposure windows. For environments where immediate patching is not feasible, network-level controls such as web filtering proxies can be configured to block access to known malicious domains or suspicious HTML content patterns associated with UI spoofing attempts. Additionally, user awareness training remains critical; educating users to verify URL bars and look for subtle discrepancies in font rendering or layout when interacting with sensitive forms can help detect spoofed interfaces even if technical controls are bypassed.