CVE-2025-58438 is a path traversal vulnerability classified under CWE-22 found in the internetarchive Python library, specifically in the File.download() method in versions 5.5.0 and earlier. The vulnerability arises because the method does not properly sanitize or validate user-supplied filenames before writing files to disk. An attacker can supply filenames containing path traversal sequences such as "../../" or illegal characters, causing the library to write files outside the intended download directory. This can result in overwriting critical system files, application configuration files, or other sensitive files on the host system. The impact varies depending on the context in which the library is used; it can lead to denial of service by corrupting essential files, privilege escalation if system files are overwritten, or remote code execution if executable files are replaced or malicious scripts are planted. The vulnerability is particularly critical on Windows systems due to the predictable locations of important system files, but all operating systems using the library are vulnerable. The vulnerability has a CVSS 4.0 base score of 9.4, indicating critical severity with network attack vector, low attack complexity, no privileges or user interaction required, and high impact on confidentiality, integrity, and availability. The issue was publicly disclosed on September 6, 2025, and fixed in version 5.5.1 of the internetarchive library. No known exploits have been reported in the wild as of now, but the critical nature and ease of exploitation make it a high-risk vulnerability for users of the affected versions.

For European organizations, this vulnerability poses a significant risk especially for those relying on the internetarchive library for automated downloads or archival processes. Exploitation can lead to unauthorized file overwrites, causing service disruptions or system instability. In environments where the library is used with elevated privileges or in automated pipelines, attackers could achieve privilege escalation or remote code execution, potentially compromising entire systems or networks. This is particularly concerning for critical infrastructure, government agencies, and enterprises that use Python-based tooling integrating this library. The ability to overwrite configuration or system files can disrupt business continuity and lead to data breaches or operational outages. The cross-platform nature of the vulnerability means organizations running Windows, Linux, or macOS are all at risk. Given the library’s role interfacing with Archive.org, organizations involved in digital preservation, research, or media may be especially exposed. The lack of known exploits currently provides a window for proactive mitigation before active attacks emerge.

European organizations should immediately upgrade the internetarchive library to version 5.5.1 or later where the vulnerability is patched. They should audit all internal and third-party codebases and pipelines that use this library to identify vulnerable versions. Implement strict input validation and sanitization on any user-supplied filenames or paths before passing them to the File.download() method. Employ application-level sandboxing or containerization to limit the filesystem scope accessible to processes using this library, minimizing potential damage from exploitation. Monitor file integrity of critical system and application files to detect unauthorized changes. Restrict permissions of the user accounts running the affected software to the minimum necessary, avoiding running with administrative or root privileges. Establish network monitoring for unusual file write activities or unexpected outbound connections that could indicate exploitation attempts. Finally, maintain an incident response plan to quickly isolate and remediate affected systems if exploitation is suspected.