BaseFortify

Publication date: 2025-11-07

Last updated on: 2025-11-12

Assigner: GitHub, Inc.

Description

Dosage is a comic strip downloader and archiver. When downloading comic images in versions 3.1 and below, Dosage constructs target file names from different aspects of the remote comic (page URL, image URL, page content, etc.). While the basename is properly stripped of directory-traversing characters, the file extension is taken from the HTTP Content-Type header. This allows a remote attacker (or a Man-in-the-Middle, if the comic is served over HTTP) to write arbitrary files outside the target directory (if additional conditions are met). This issue is fixed in version 3.2.

CVSS Scores

EPSS Scores

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Meta Information

Published

2025-11-07

Last Modified

2025-11-12

Generated

2026-07-06

AI Q&A

2025-11-07

EPSS Evaluated

2026-07-05

NVD

CVE-2025-64184

Affected Vendors & Products

Vendor	Product	Version / Range
webcomics	dosage	3.1
webcomics	dosage	3.2

Helpful Resources

Exploitability

CWE

KEV

CWE ID	Description
CWE-22	The product uses external input to construct a pathname that is intended to identify a file or directory that is located underneath a restricted parent directory, but the product does not properly neutralize special elements within the pathname that can cause the pathname to resolve to a location that is outside of the restricted directory.

Attack-Flow Graph

Executive Summary

This vulnerability exists in Dosage versions 3.1 and below, where the software downloads comic images and constructs target file names using information from the remote comic. Although the base file name is sanitized to remove directory-traversing characters, the file extension is taken directly from the HTTP Content-Type header. This flaw allows a remote attacker or a Man-in-the-Middle (if the comic is served over HTTP) to manipulate the file extension and potentially write arbitrary files outside the intended target directory, leading to unauthorized file creation or overwriting.

Impact Analysis

This vulnerability can lead to an attacker writing arbitrary files outside the intended directory on the victim's system. This can result in unauthorized file creation or modification, potentially leading to system compromise, data corruption, or denial of service. Because the vulnerability allows for arbitrary file writes, it can severely impact the confidentiality, integrity, and availability of the affected system.

Mitigation Strategies

Upgrade Dosage to version 3.2 or later, as this version fixes the vulnerability. Avoid using versions 3.1 and below to prevent exploitation.

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