CVE-2026-66310 in Edge
Summary
by MITRE • 08/04/2026
External control of file name or path in Microsoft Edge for Android allows an unauthorized attacker to disclose information locally.
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Analysis
by VulDB Data Team • 08/04/2026
This vulnerability represents a critical security flaw in Microsoft Edge for Android that stems from improper validation of file paths and names in external control scenarios. The issue arises when the browser application fails to adequately sanitize user-supplied input that influences file system operations, creating a path traversal condition that can be exploited by malicious actors. The vulnerability is classified under CWE-22 as "Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')" and aligns with ATT&CK technique T1059.007 for "Command and Scripting Interpreter: JavaScript" when exploited through browser-based attack vectors.
The technical implementation flaw occurs within the Edge browser's handling of external file references where user-controllable parameters can influence the file system path resolution process. When an attacker can manipulate how file paths are constructed or resolved, they gain the ability to navigate beyond intended directories and access sensitive local files that should remain protected. This typically manifests when the application concatenates user input directly into file system operations without proper validation or sanitization, allowing attackers to inject malicious path components such as ../ or ..\ sequences.
The operational impact of this vulnerability extends beyond simple information disclosure, as it can potentially lead to complete system compromise if sensitive files containing credentials, configuration data, or personal information are accessible through the exploited path traversal mechanism. Attackers can leverage this weakness to access browser cache files, downloaded content, local storage databases, and other sensitive resources that should be isolated from external manipulation. The vulnerability is particularly concerning in mobile environments where browsers often have broader file system access permissions than desktop counterparts.
Mitigation strategies must address both immediate remediation and long-term architectural improvements. Organizations should implement strict input validation mechanisms that sanitize all user-supplied data before any file system operations occur, employing techniques such as canonicalization checks and absolute path verification. The browser should enforce mandatory sandboxing of file operations and restrict access to sensitive directories through proper privilege separation. Additionally, implementing proper output encoding for file paths and utilizing secure coding practices that prevent direct concatenation of user input with file system calls can significantly reduce the attack surface. Regular security assessments and code reviews focusing on path handling routines should be conducted to identify similar vulnerabilities across the application ecosystem.