CVE-2026-121051 in Chrome
Summary
by MITRE • 11/03/2026
UI misrepresentation in iOSWeb in Google Chrome on on iOS prior to 157.0.8103.38 allowed a remote attacker to spoof address bar via a crafted HTML page. (Chromium security severity: High)
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Analysis
by VulDB Data Team • 11/03/2026
The vulnerability identified as UI misrepresentation in the WebKit engine utilized by Google Chrome on iOS prior to version 157.0.8103.38 represents a significant trust boundary violation within the browser's user interface layer. This flaw specifically affects the rendering of the address bar, which serves as the primary visual indicator for users regarding the authenticity and origin of the web content they are viewing. By exploiting this issue, a remote attacker can manipulate the display logic to present a deceptive URL that differs from the actual destination of the page being loaded. This technique relies on sophisticated CSS styling or JavaScript-based DOM manipulation techniques designed to overlay fake address bar elements atop the legitimate browser chrome, effectively creating a visual illusion where the user believes they are interacting with a trusted domain while their inputs and interactions are directed toward an attacker-controlled server.
From a technical perspective, this vulnerability falls under the category of UI Redressing attacks, which exploit discrepancies between what is rendered visually to the end-user and the actual network requests being transmitted by the browser engine. The root cause lies in how Chrome on iOS handles layering and z-index properties for its native interface components relative to web content. When a crafted HTML page employs specific positioning techniques or transparency effects, it can obscure the real address bar with a counterfeit version that displays a legitimate-looking domain name. This misrepresentation breaks the fundamental security assumption that the browser's UI accurately reflects the current navigation state and URL scheme. The severity is classified as High because this type of attack directly undermines user trust in the browsing environment, which is critical for preventing credential theft and other social engineering attacks.
The operational impact of this vulnerability is severe, primarily facilitating phishing campaigns with high success rates. Attackers can host malicious pages that mimic popular banking institutions, email providers, or e-commerce platforms while displaying a URL that appears safe to the user. Since mobile browsers often have limited screen real estate compared to desktop counterparts, users are more reliant on visual cues such as the address bar for security assessment. If an attacker successfully spoofs this element, victims may inadvertently submit sensitive information such as login credentials, credit card numbers, or personal identification details to a malicious endpoint without realizing they have left the legitimate site. This creates a direct pathway for account takeover and financial fraud, leveraging the user's trust in both the browser vendor and their own perception of safety.
In terms of industry standards classification, this vulnerability aligns with CWE-1021: Improper Restriction of Rendered UI Layers or Frames, which describes flaws where an application fails to properly restrict how different layers of a graphical interface are rendered relative to one another. Furthermore, from the perspective of the MITRE ATT&CK framework, this technique is categorized under T1657: Spoofing Feedback, specifically within the context of user interface deception. It also relates closely to T1059: Command and Scripting Interpreter if used in conjunction with further exploitation steps, but primarily it serves as a delivery mechanism for social engineering attacks like Phishing (T1566). The attack vector is classified as Remote via Network, requiring no local access or user interaction beyond visiting the malicious webpage.
Mitigation strategies focus on both immediate patching and long-term architectural improvements. Users must update Google Chrome to version 157.0.8103.38 or later on iOS devices, as this release contains specific fixes for WebKit rendering behaviors that prevent the overlay of fake UI elements over native browser controls. Browser vendors should continue to implement strict origin isolation and ensure that critical security indicators like the address bar are rendered in a separate process layer that cannot be easily obscured by web content. Additionally, users can mitigate risk by manually verifying URLs through secondary channels or using password managers that rely on domain binding rather than visual inspection alone. Security awareness training remains essential to remind users that even trusted-looking interfaces can be compromised if software is not kept up to date with the latest security patches addressing UI redressing vulnerabilities.