CVE-2026-106398 in Chrome
Summary
by MITRE • 10/07/2026
Incorrect authorization in Media in Google Chrome prior to 155.0.8059.39 allowed a remote attacker to leak cross-origin data 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 flaw within the media subsystem of Google Chrome, specifically affecting versions prior to 155.0.8059.39, represents a significant breach in cross-origin isolation mechanisms. This issue stems from improper access control checks implemented when handling multimedia content requests. In modern web browsers, the same-origin policy is a critical security concept that restricts how documents or scripts loaded from one origin can interact with resources from another origin. When this boundary is compromised due to flawed authorization logic within the media pipeline, it allows for unauthorized data exfiltration across domain boundaries. The severity of this vulnerability is classified as medium by the Chromium team, indicating a balance between exploitability and impact, yet its potential for privacy violation remains substantial in targeted attack scenarios.
From a technical perspective, the flaw resides in how Chrome processes requests related to media elements when they are embedded within or triggered by HTML pages hosted on different domains. A remote attacker could craft a malicious webpage designed to trigger specific media loading behaviors that bypass standard cross-origin checks. By leveraging this misconfiguration, an attacker can access sensitive information associated with media resources from other origins without proper user consent or authentication. This typically involves manipulating the browser's internal state management for media sessions, allowing the crafted page to read data such as metadata, playback status, or potentially more sensitive content if the media resource itself contains confidential information. The attack vector is remote and requires no special privileges on the victim's system other than visiting a malicious website, which aligns with common web-based exploitation techniques where social engineering or drive-by downloads serve as initial access methods.
The operational impact of this vulnerability centers on data leakage and privacy violations. An attacker successfully exploiting this flaw could gather cross-origin data that should remain isolated within its original domain context. This might include identifying user interests based on media consumption, extracting unique identifiers embedded in media files, or accessing private content if the victim has authenticated sessions active for those specific domains. Such information can be used to build detailed profiles of users, facilitate further targeted attacks like phishing, or simply violate privacy regulations such as GDPR or CCPA depending on the nature of the leaked data. The ability to leak cross-origin data undermines the fundamental trust model of web browsing, where users expect that content from one site cannot silently spy on activities related to another trusted site open in a different tab or window.
To mitigate this risk, organizations and individual users must ensure that Google Chrome is updated to version 155.0.8059.39 or later immediately upon availability. This patch addresses the underlying authorization logic errors within the media subsystem, restoring proper cross-origin isolation boundaries. For enterprise environments, enforcing automatic browser updates through centralized management tools can prevent exposure during the window between vulnerability disclosure and remediation. Additionally, users should employ strict content security policies where applicable and consider using extensions that enhance privacy protection by blocking unauthorized data transfers or restricting third-party cookie access. Monitoring for unusual network traffic patterns originating from browser processes may also help detect potential exploitation attempts in real-time.
This incident is categorized under CWE-269, which refers to Improper Authorization, as the core failure lies in the system not correctly enforcing permissions before allowing access to restricted resources. Furthermore, it aligns with MITRE ATT&CK technique T1059, specifically sub-techniques related to command and script interpretation or potentially data exfiltration over alternative protocols if the media stream is manipulated for covert channels. Understanding these classifications helps security teams map this vulnerability to broader threat landscapes and prioritize remediation efforts based on industry-standard frameworks. The resolution emphasizes the importance of rigorous code review processes focused on access control mechanisms, particularly in complex subsystems like multimedia handling where state management can become intricate and prone to logical errors if not carefully validated against all possible input vectors from untrusted sources.