CVE-2026-21133 in Flow
Summary
by MITRE • 10/12/2026
Path traversal in Samsung Flow prior to version 4.9.22.1 allows local attackers to access clipboard data.
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Analysis
by VulDB Data Team • 10/12/2026
The vulnerability identified as a path traversal flaw within Samsung Flow versions prior to 4.9.22.1 represents a critical security deficiency that compromises the confidentiality of user data on affected devices. This specific weakness arises from improper validation of file paths or resource identifiers processed by the application, allowing local attackers to manipulate input parameters in ways that bypass intended access controls. By exploiting this path traversal mechanism, an attacker can navigate outside the designated secure directories and reach sensitive system locations where clipboard contents are stored or cached. The core technical flaw lies in the failure to sanitize user-supplied inputs effectively before they are used as file paths, a classic implementation error often categorized under CWE-22: Improper Limitation of a Pathname to a Restricted Directory. This lack of rigorous input validation enables the construction of maliciously crafted requests that utilize directory traversal sequences or relative path manipulations to access files outside the application's sandboxed environment.
From an operational perspective, the ability for local attackers to read clipboard data has significant implications for user privacy and security hygiene. Clipboard managers often retain a history of copied text, images, and other sensitive information such as passwords, personal identification numbers, financial details, or private communications. When this data is accessible via path traversal, it effectively bypasses standard operating system permissions that would otherwise restrict access to clipboard contents from untrusted applications. This vulnerability aligns with the ATT&CK technique T1056.004: Clipboard Data, which describes how adversaries can intercept and exfiltrate information currently stored in the clipboard memory. The impact is particularly severe because it requires no remote exploitation vector; instead, any local application or script running on the compromised device can potentially trigger this flaw to harvest sensitive data without user interaction beyond initial execution of the malicious payload.
The severity of this issue is compounded by the nature of modern mobile and desktop ecosystems where clipboard functionality is deeply integrated into daily workflows. Users frequently copy complex strings including API keys, session tokens, or confidential messages between applications. If an attacker can programmatically access these buffers through a path traversal exploit in a trusted application like Samsung Flow, they gain a persistent foothold for data exfiltration that may go undetected by standard security monitoring tools. The vulnerability highlights the risks associated with privileged local services and third-party integrations that handle sensitive user inputs without adequate isolation or validation mechanisms. It underscores the importance of strict input sanitization and principle of least privilege in application design, ensuring that even if an attacker gains execution context within a specific app boundary, they cannot escalate their access to broader system resources like clipboard memory through file path manipulation.
To mitigate this vulnerability, users must immediately update Samsung Flow to version 4.9.22.1 or later, where the developers have implemented fixes for the underlying input validation logic. Security best practices dictate that applications handling sensitive data should employ allow-listing strategies for file paths rather than relying on block lists of malicious characters. Additionally, implementing strict sandboxing and capability restrictions can limit the damage even if a path traversal attempt is successful. For system administrators and security teams, it is crucial to monitor for unusual access patterns to clipboard-related files or processes that indicate exploitation attempts. Regular patch management remains the most effective defense against such known vulnerabilities, ensuring that applications are protected against previously disclosed flaws in their codebase.