CVE-2025-64184 is a path traversal vulnerability classified under CWE-22 found in Dosage, a tool used for downloading and archiving comic strips. In versions 3.1 and below, Dosage constructs filenames for downloaded comic images by combining sanitized basenames derived from URLs and page content with file extensions extracted directly from the HTTP Content-Type header. While the basename is properly sanitized to remove directory traversal characters (such as '../'), the file extension is not validated or sanitized. This oversight allows an attacker who can control or manipulate the HTTP response headers—either remotely or via a man-in-the-middle (MitM) attack on unencrypted HTTP connections—to specify malicious file extensions containing directory traversal sequences. Consequently, the attacker can cause Dosage to write files outside the intended download directory, potentially overwriting critical system files or placing malicious payloads in sensitive locations. The vulnerability does not require authentication but does require user interaction to initiate the download process. The CVSS 3.1 score of 8.8 reflects the high impact on confidentiality, integrity, and availability, combined with low attack complexity and no privileges required. The issue was publicly disclosed on November 7, 2025, and fixed in Dosage version 3.2. No known exploits are reported in the wild yet, but the vulnerability presents a significant risk due to the ease of exploitation and potential damage.

For European organizations, the impact of CVE-2025-64184 can be substantial, particularly for entities relying on Dosage for digital archiving or content management of webcomics and similar media. Successful exploitation can lead to arbitrary file writes outside the designated directories, enabling attackers to overwrite critical files, implant malware, or disrupt service availability. This can compromise system confidentiality by exposing sensitive files, integrity by altering or replacing legitimate files, and availability by corrupting essential system components or causing application failures. Organizations in sectors such as digital media, cultural heritage archiving, and creative industries may be particularly vulnerable. Additionally, if Dosage is used in automated workflows or integrated with other systems, the risk of lateral movement or broader compromise increases. The vulnerability is exacerbated in environments where HTTP is still used instead of HTTPS, as MitM attackers can manipulate HTTP headers to exploit the flaw. Given the high CVSS score and the potential for significant damage, European organizations should prioritize addressing this vulnerability to avoid operational disruption and data breaches.

1. Upgrade Dosage to version 3.2 or later immediately, as this version includes the fix for the path traversal vulnerability. 2. If upgrading is not immediately possible, implement strict validation and sanitization of the HTTP Content-Type header before using it to determine file extensions, ensuring no directory traversal sequences or unexpected characters are allowed. 3. Prefer downloading comics over secure HTTPS connections to prevent man-in-the-middle manipulation of HTTP headers. 4. Employ application-level sandboxing or run Dosage with least privilege to limit the impact of any arbitrary file writes. 5. Monitor file system changes in directories used by Dosage for unexpected or unauthorized file creations or modifications. 6. Educate users about the risks of downloading content from untrusted sources and encourage vigilance when using tools that fetch remote content. 7. Consider network-level protections such as HTTPS enforcement and intrusion detection systems to detect anomalous traffic patterns indicative of exploitation attempts.