CVE-2026-53906 in MCO
Summary
by MITRE • 07/01/2026
MCO is vulnerable to Path Disclosure and Path Traversal in file handling functionality related to data export and upload. Improper validation of the filename parameter allows writing files to arbitrary locations as well as indirect disclosure of absolute server paths through error messages.
Because vendor contact attempts were unsuccessful, the vulnerability has only been confirmed in version 25.3.3.1 but may also affect other versions.
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Analysis
by VulDB Data Team • 07/01/2026
This vulnerability represents a critical security flaw in MCO's file handling mechanisms that exposes the system to both path disclosure and path traversal attacks. The issue stems from inadequate validation of filename parameters within the data export and upload functionality, creating a dangerous condition where malicious actors can manipulate file paths to write data to arbitrary locations on the server filesystem. The vulnerability manifests through improper input sanitization that fails to properly validate or sanitize user-supplied filename values before processing them in file operations.
The technical implementation flaw allows attackers to exploit the lack of proper path validation by injecting malicious path sequences such as ../ or ..\ into the filename parameter. This enables attackers to traverse the directory structure and potentially write files outside of intended directories, leading to unauthorized data modification or even remote code execution depending on the server configuration and permissions. The path disclosure aspect occurs through error messages that inadvertently reveal absolute server paths, providing attackers with valuable information about the underlying file system structure and potentially aiding in further exploitation attempts.
The operational impact of this vulnerability is severe as it compromises the integrity and confidentiality of the affected system. Attackers can leverage this flaw to gain unauthorized access to sensitive data, modify critical system files, or establish persistent backdoors through file placement in strategic locations. The indirect disclosure of absolute paths through error messages creates additional attack surface by providing attackers with information that could be used in conjunction with other vulnerabilities to craft more sophisticated attacks. This weakness violates several security principles including least privilege and input validation, making it particularly dangerous in enterprise environments where data protection is paramount.
The vulnerability's classification aligns with CWE-22 Path Traversal and CWE-200 Information Exposure, both of which are fundamental security concerns that require immediate attention. From an ATT&CK framework perspective, this vulnerability maps to T1059 Command and Scripting Interpreter and T1078 Valid Accounts, as it enables attackers to gain access to the underlying system through file manipulation techniques. Given that the vendor contact attempts were unsuccessful, the confirmed version 25.3.3.1 may represent only a subset of affected versions, suggesting that other releases in the product line could be equally vulnerable and require immediate assessment.
Organizations should implement immediate mitigations including thorough input validation for all filename parameters, implementing proper path sanitization functions that reject or normalize potentially dangerous path sequences, and ensuring that file operations occur within designated safe directories. The system should also be configured to suppress detailed error messages that might reveal absolute paths and instead provide generic error responses. Additionally, implementing a principle of least privilege for file system access and regular security audits of file handling functions will help prevent exploitation of this vulnerability. The lack of vendor response underscores the importance of proactive security measures and independent verification of security controls within critical infrastructure components.