CVE-2026-106226 in Chrome
Summary
by MITRE • 10/06/2026
Improper input validation in Compositing in Google Chrome prior to 155.0.8059.39 allowed a remote attacker who had compromised the renderer process to spoof address bar 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 improper input validation flaw within the compositing subsystem of Google Chrome prior to version 155.0.8059.39 represents a significant breach in browser UI integrity, specifically targeting the address bar spoofing vector. This class of vulnerabilities falls under the broader category of CWE-20 Improper Input Validation, where the application fails to adequately verify or sanitize data before processing it within critical security boundaries. In this specific instance, the flaw resides in how the rendering engine handles graphical composition operations when interacting with user interface elements such as the omnibox. The technical mechanism involves a race condition or state inconsistency during the compositing phase, allowing a maliciously crafted HTML page to manipulate the visual layering and positioning of UI components relative to the content being rendered. By exploiting this discrepancy, an attacker can overlay deceptive text or graphical elements over the actual address bar, creating a convincing illusion that the user is on a legitimate site while they are actually viewing content from a different origin.
From an operational perspective, this vulnerability enables a sophisticated phishing attack vector known as UI redressing or clickjacking variants tailored for browser chrome spoofing. The primary impact is the erosion of trust in the security indicators provided by the browser interface. Users rely heavily on the address bar to verify domain names and certificate validity before entering sensitive information such as credentials, credit card numbers, or personal data. When an attacker can successfully spoof this element, they bypass these critical user-assisted verification steps. This leads directly to credential theft, session hijacking, and potential malware installation if the spoofed page prompts for downloads. The severity is classified as medium by Chromium security standards because it requires a compromised renderer process context or successful exploitation of another vulnerability in that sandboxed environment to execute the attack, yet its impact on user trust and data confidentiality is high due to the direct manipulation of trusted UI elements.
This behavior aligns with several techniques documented in the MITRE ATT&CK framework for enterprise security monitoring and threat analysis. Specifically, it relates to T1078 Valid Accounts if used in conjunction with credential harvesting from legitimate sessions, but more accurately maps to T1498 Network Denial of Service or UI manipulation tactics often seen in advanced persistent threats aiming to bypass user awareness controls. It also intersects with CWE-352 Cross-Site Request Forgery principles where the visual context is manipulated to trick users into performing unintended actions, although here the focus is on deception rather than forced state changes. The exploitation typically involves crafting an HTML page that leverages CSS positioning and JavaScript timing attacks to synchronize the spoofed overlay with the browser's rendering cycle, ensuring it appears seamlessly without flickering or layout shifts that might alert a vigilant user.
Mitigation strategies for this vulnerability primarily involve updating Google Chrome to version 155.0.8059.39 or later, where these input validation checks in the compositing pipeline have been hardened. For organizations managing large fleets of endpoints, deploying automated patch management solutions is essential to ensure timely remediation across all user devices. Additionally, security awareness training should emphasize verifying domain names manually rather than relying solely on visual cues within the address bar, as sophisticated spoofing techniques can mimic legitimate branding and layout structures effectively. Implementing strict Content Security Policies (CSP) with directives that restrict frame-ancestors and other UI-manipulating features can also reduce the attack surface by preventing external or untrusted content from influencing browser chrome elements. Regular security audits focusing on renderer process isolation and input validation logic in web rendering engines are recommended to detect similar flaws before they reach production releases.