CVE-2025-69621 Overview
An arbitrary file overwrite vulnerability exists in the file import process of Comic Book Reader v1.0.95. This security flaw allows attackers to overwrite critical internal files during the import operation, potentially leading to arbitrary code execution or exposure of sensitive information stored within the application's directory structure.
Critical Impact
Attackers can exploit the file import functionality to overwrite protected files, enabling arbitrary code execution or unauthorized access to sensitive user data.
Affected Products
- Comic Book Reader v1.0.95
Discovery Timeline
- 2026-02-04 - CVE-2025-69621 published to NVD
- 2026-02-04 - Last updated in NVD database
Technical Details for CVE-2025-69621
Vulnerability Analysis
This arbitrary file overwrite vulnerability occurs during the file import process within Comic Book Reader. The application fails to properly validate or sanitize file paths during the import operation, allowing malicious actors to craft specially constructed import files that can overwrite arbitrary files on the system.
The vulnerability falls under the category of path traversal combined with arbitrary file write. When a user imports a comic book file (such as CBZ or CBR formats, which are essentially archive files), the application extracts contents without adequately verifying the destination paths. This allows attackers to include path traversal sequences or absolute paths within the archive that escape the intended extraction directory.
The impact of this vulnerability is significant as it can lead to two primary attack scenarios: arbitrary code execution through overwriting executable components or configuration files, and information disclosure through overwriting files with attacker-controlled content that gets processed by other application components.
Root Cause
The root cause of this vulnerability is insufficient input validation in the file import handler of Comic Book Reader. The application does not properly sanitize file paths contained within imported archive files, failing to prevent directory traversal sequences (such as ../) or absolute paths from being used during extraction. This oversight allows malicious archives to write files outside the intended extraction directory.
Attack Vector
The attack vector involves crafting a malicious comic book archive file (CBZ/CBR) containing path traversal sequences in its internal file structure. When a victim imports this specially crafted file using Comic Book Reader v1.0.95, the application extracts the contents and follows the malicious paths, overwriting critical files outside the designated directory.
An attacker could target application configuration files, shared libraries, or user data files. If the application runs with elevated privileges or if the overwritten files are executed during normal operation, this could lead to arbitrary code execution. Alternatively, overwriting configuration files could allow persistence mechanisms or credential theft.
The vulnerability requires user interaction (importing a malicious file) but does not require authentication to the application itself. Technical details and proof-of-concept information can be found in the GitHub Issue Tracker maintained by the Fudan Secsys Research team.
Detection Methods for CVE-2025-69621
Indicators of Compromise
- Unexpected file modifications in application directories or parent directories following comic book file imports
- Presence of files with unusual names or path structures in system directories that correlate with Comic Book Reader usage
- Modified application binaries, configuration files, or library files with timestamps matching import operations
Detection Strategies
- Monitor file system activity during Comic Book Reader import operations for writes outside the expected extraction directory
- Implement file integrity monitoring on critical application files and system directories
- Analyze imported archive files for path traversal sequences (../, absolute paths) before extraction
Monitoring Recommendations
- Enable verbose logging for file system operations associated with Comic Book Reader processes
- Set up alerts for file modifications in protected directories when Comic Book Reader is the originating process
- Review import activity logs for suspicious file patterns or repeated failed operations that may indicate exploitation attempts
How to Mitigate CVE-2025-69621
Immediate Actions Required
- Avoid importing comic book files from untrusted or unknown sources until a patch is available
- Consider temporarily disabling or restricting the file import functionality if feasible
- Run Comic Book Reader with minimal privileges to limit the impact of potential file overwrites
- Implement application sandboxing to contain file operations within a restricted directory
Patch Information
No official patch information is currently available from the vendor. Users should monitor the official Comic Book Reader release channels and the GitHub Issue Tracker for updates regarding security fixes. Consider upgrading to newer versions when available, after verifying the vulnerability has been addressed.
Workarounds
- Use alternative comic book reader applications that implement proper path validation during archive extraction
- Scan imported comic book files with archive inspection tools to detect path traversal sequences before opening with Comic Book Reader
- Run Comic Book Reader in a sandboxed environment (container or virtual machine) to isolate potential file system impacts
- Implement file system access controls to prevent the application from writing outside its designated directories
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
