CVE-2026-66050 in NitroShare
Summary
by MITRE • 07/27/2026
NitroShare Desktop through 0.3.4 contains a path traversal vulnerability in its LAN file transfer server that allows unauthenticated attackers on the same network to write arbitrary files by sending a crafted filename containing directory traversal sequences in the JSON item header name field. Attackers can exploit the lack of path validation to write files outside the transfer root directory to arbitrary locations the current user has write access, including the Windows Startup folder, enabling persistent code execution on the next user login.
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Analysis
by VulDB Data Team • 07/27/2026
The NitroShare Desktop application version 0.3.4 and earlier contains a critical path traversal vulnerability that fundamentally compromises system security through its LAN file transfer functionality. This vulnerability exists within the application's server component that handles file transfers across local networks, creating an exploitable condition where remote attackers can manipulate file paths during the transfer process. The flaw specifically manifests in the JSON item header name field processing, where the application fails to properly validate or sanitize user-supplied filenames before writing them to disk.
The technical implementation of this vulnerability stems from inadequate input validation mechanisms within the file transfer server code. When processing incoming file transfer requests, the system directly uses the filename provided in the JSON header without proper sanitization or path resolution checks. This allows attackers to craft malicious filenames containing directory traversal sequences such as ../ or ..\ that bypass normal file system access controls and permissions. The vulnerability operates at the application layer rather than relying on operating system level flaws, making it particularly dangerous as it can be exploited without requiring elevated privileges beyond network access.
From an operational perspective, this vulnerability creates significant risk for users who have NitroShare running on their systems, especially in shared network environments such as corporate offices or educational institutions. The attack vector requires only local network access and does not necessitate authentication, making it particularly dangerous in environments where network segmentation is inadequate. An attacker can leverage this vulnerability to write malicious files to critical system locations including the Windows Startup folder, which automatically executes programs during user login processes. This persistent execution capability transforms what might otherwise be a one-time exploitation into a long-term foothold within the compromised system.
The security implications extend beyond simple file manipulation as this vulnerability enables potential privilege escalation and persistence mechanisms. When malicious files are written to locations like the Windows Startup folder or other system directories with write permissions, they can execute automatically during user sessions, providing attackers with ongoing access to the compromised system. This aligns with attack patterns documented in the MITRE ATT&CK framework under T1068 for local privilege escalation and T1547 for account policy modification, though the specific execution method here leverages the application's own file handling capabilities rather than traditional privilege escalation techniques.
Organizations should immediately implement network segmentation to isolate systems running NitroShare from critical infrastructure and ensure that only trusted users have access to these systems. The most effective immediate mitigation involves updating to version 0.3.5 or later, which includes proper input validation and path sanitization mechanisms. Additionally, network administrators should consider implementing firewall rules to restrict access to the application's ports and services, while security teams should monitor for unusual file creation patterns in system directories that might indicate exploitation attempts. The vulnerability also highlights the importance of input validation principles as outlined in CWE-22, which specifically addresses path traversal flaws in software applications.
System administrators should conduct immediate vulnerability assessments across their network to identify systems running affected versions of NitroShare and ensure proper patch management procedures are in place for similar applications. The incident demonstrates the critical need for secure coding practices, particularly around file system operations and input validation, as recommended by industry standards including OWASP Top Ten and NIST cybersecurity guidelines. Organizations should also consider implementing application whitelisting policies to prevent unauthorized execution of potentially malicious files created through such vulnerabilities, while maintaining comprehensive logging and monitoring of file system activities to detect anomalous behavior patterns that might indicate exploitation attempts.