CVE-2026-106406 in Chrome
Summary
by MITRE • 10/07/2026
Missing authorization in Mobile in Google Chrome on on iOS prior to 155.0.8059.39 allowed a remote attacker leveraging social engineering 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 missing authorization within the mobile implementation of Google Chrome on iOS prior to version 155.0.8059.39 represents a significant flaw in how user interface components are rendered and authenticated during web page interactions. This issue stems from an insufficient check regarding whether the browser should display specific UI elements or overlays when processing content from untrusted sources. In modern mobile browsers, the rendering engine often integrates native iOS controls with HTML-based interfaces to provide seamless navigation experiences. When this integration lacks proper authorization checks, it creates a pathway for attackers to manipulate what the user perceives as part of the operating system rather than the web page itself. The Chromium project has classified this security severity as Medium, indicating that while exploitation requires specific conditions such as social engineering, the potential impact on user trust and data integrity is substantial enough to warrant immediate attention.
The technical mechanism behind this vulnerability involves the manipulation of UI spoofing through crafted HTML pages. An attacker can construct a malicious webpage designed to mimic legitimate system dialogs or navigation bars by exploiting the lack of authorization checks in how Chrome renders these elements on iOS devices. By leveraging CSS styling, JavaScript event handlers, and potentially iframe injection techniques, an adversary can overlay fake login prompts, permission requests, or warning messages that appear indistinguishable from genuine Apple or Google interface components. This technique relies heavily on social engineering to trick users into interacting with the spoofed elements. Since the visual presentation is controlled by the web page rather than a secure system-level dialog box, there is no cryptographic guarantee of authenticity for the user. Consequently, victims may inadvertently enter sensitive credentials, grant unnecessary permissions, or download malicious payloads believing they are responding to official prompts from their device manufacturer or browser provider.
From an operational impact perspective, this vulnerability undermines the fundamental trust model that users place in mobile browsers and operating systems. The primary consequence is credential theft through phishing attacks that bypass traditional visual cues of authenticity. Users who encounter these spoofed UI elements may surrender usernames, passwords, two-factor authentication codes, or financial information to attackers posing as legitimate services such as banks, email providers, or social media platforms. Beyond direct data loss, this vulnerability erodes user confidence in the security posture of mobile browsers and can lead to broader adoption of malicious software if users are tricked into installing profiles or executing scripts under false pretenses. The attack vector is remote, meaning no prior access to the victim's device is required, making it scalable for large-scale phishing campaigns targeting iOS users who rely on Chrome as their primary browsing tool.
To mitigate this risk, organizations and individual users must prioritize updating Google Chrome to version 155.0.8059.39 or later immediately upon availability. This update contains the necessary patches that enforce strict authorization checks before rendering UI elements derived from web content. Administrators should implement automated patch management policies for mobile devices within enterprise environments to ensure timely deployment of security updates. Additionally, users can adopt defensive browsing habits such as verifying URLs manually in the address bar rather than relying solely on visual cues provided by page overlays. Enabling safe browsing features and keeping iOS itself updated further reduces the attack surface associated with browser-specific vulnerabilities. Security awareness training should also emphasize recognizing signs of UI spoofing, including subtle discrepancies in font rendering, spacing, or behavior that differ from native system dialogs.
This vulnerability aligns with CWE-287, which describes Improper Authentication, specifically where an actor is able to impersonate another by exploiting weaknesses in the authentication process related to user interface elements. It also maps to MITRE ATT&CK technique T1036, known as Masquerading, wherein attackers disguise their actions or tools to appear legitimate. By addressing this flaw through software updates and reinforcing user vigilance against social engineering tactics that exploit UI inconsistencies, stakeholders can effectively neutralize the threat posed by these sophisticated phishing attempts targeting mobile browser users.