CVE-2026-121209 in Chrome
Summary
by MITRE • 11/03/2026
UI misrepresentation in Input in Google Chrome prior to 157.0.8103.38 allowed a remote attacker to spoof address bar via a crafted HTML page. (Chromium security severity: Low)
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Analysis
by VulDB Data Team • 11/03/2026
The vulnerability identified as UI misrepresentation in input within Google Chrome versions prior to 157.0.8103.38 represents a classic user interface deception flaw that exploits the browser's rendering engine to create a discrepancy between what is displayed on screen and the actual data being processed or submitted by the application. This specific issue allows a remote attacker, through the delivery of a maliciously crafted HTML page, to manipulate the visual representation of input fields in such a way that they appear legitimate while potentially masking their true nature or destination. The core technical flaw lies in how the browser handles certain CSS properties and JavaScript interactions during the layout phase, where an adversary can overlay deceptive elements over genuine interface components or alter the perceived context of user inputs without triggering standard security warnings associated with mixed content or certificate errors. By leveraging this misrepresentation, an attacker can trick users into entering sensitive information such as credentials, personal identifiable data, or financial details under the false impression that they are interacting with a trusted and authentic service rather than a phishing site designed to harvest these values for malicious purposes.
From an operational impact perspective, while Chromium classifies this vulnerability with a low security severity rating due to its reliance on social engineering and user interaction, it remains highly dangerous in real-world attack scenarios because it bypasses traditional technical controls that focus solely on network-level threats or code execution vulnerabilities. The ability to spoof the address bar is particularly critical as users rely heavily on visual cues like domain names and lock icons to verify identity; when these cues are manipulated through UI tricks rather than actual protocol exploits, trust mechanisms fail silently without raising alarms in standard security monitoring tools. This type of attack falls squarely under the category of phishing and credential harvesting, where the primary vector is not a software bug that allows remote code execution but rather a psychological manipulation enabled by technical inaccuracies in rendering logic. The impact extends beyond immediate data theft to include long-term reputational damage for targeted organizations if their brand identity is used within these spoofed interfaces, leading users to believe they are communicating with legitimate entities while actually submitting data to attacker-controlled servers.
In terms of industry standards and threat modeling, this vulnerability aligns closely with CWE-201: Information Exposure Through UI Misrepresentation, which covers scenarios where a user interface displays information that is misleading or inaccurate regarding the security state or identity of the application context. Furthermore, it maps directly to MITRE ATT&CK technique T1568.002: Dynamic Resolution, specifically when used in conjunction with domain fronting or subdomain spoofing techniques to evade detection and maintain persistence during phishing campaigns. The attack vector is classified as remote via network (Network) requiring user interaction (User Interaction), emphasizing that exploitation depends on the victim visiting a malicious webpage constructed by the adversary. Defenses against this class of vulnerability are inherently challenging because they require balancing usability with strict security constraints, often necessitating browser-level updates rather than simple configuration changes.
Mitigation strategies primarily involve updating Google Chrome to version 157.0.8103.38 or later, where the rendering engine has been patched to correctly enforce separation between visual presentation and underlying data binding logic. Users should also be educated on verifying URL details manually by clicking into the address bar rather than relying solely on its appearance in the page body, as some UI spoofing techniques only affect elements rendered within the webpage content area while leaving the actual browser chrome unaffected or subtly altered. Additionally, deploying advanced phishing protection services that utilize machine learning to detect anomalous layout structures and suspicious DOM manipulations can provide an additional layer of defense against these sophisticated social engineering attacks enabled by such rendering flaws.