CVE-2024-8088: CPython zipfile.Path DOS Vulnerability

CVE-2024-8088 Overview

A denial of service vulnerability exists in the CPython zipfile module, specifically affecting the zipfile.Path class. When iterating over names of entries in a zip archive using methods like namelist(), iterdir(), and similar functions, a maliciously crafted zip archive can cause the process to enter an infinite loop. This vulnerability impacts applications that process user-controlled zip archives, whether reading metadata or extracting contents. Notably, the more commonly used zipfile.ZipFile class is unaffected by this vulnerability.

Critical Impact

Applications processing untrusted zip files using zipfile.Path can be forced into an infinite loop, resulting in denial of service through CPU exhaustion. This affects any Python application that handles user-supplied zip archives for extraction or metadata inspection.

Affected Products

• CPython zipfile.Path module (all versions prior to patched releases)
• Python applications using zipfile.Path for zip archive processing
• Systems processing user-controlled zip archives

Discovery Timeline

• August 22, 2024 - CVE-2024-8088 published to NVD
• November 3, 2025 - Last updated in NVD database

Technical Details for CVE-2024-8088

Vulnerability Analysis

This vulnerability is classified as CWE-835 (Loop with Unreachable Exit Condition), commonly known as an infinite loop vulnerability. The flaw resides in the zipfile.Path class implementation within CPython's standard library. When processing specially crafted zip archives, the iteration logic over archive entries fails to properly terminate, causing the program to consume CPU resources indefinitely.

The attack is network-accessible, requiring no authentication or user interaction to exploit. While the vulnerability does not directly compromise data confidentiality or integrity, it severely impacts system availability by rendering the affected process unresponsive. Applications that accept zip file uploads or process zip archives from external sources are particularly at risk.

Root Cause

The root cause lies in improper handling of entry iteration within the zipfile.Path class. When encountering malformed or specially constructed archive entries, the internal iteration mechanism fails to reach its exit condition, resulting in an infinite loop. This differs from the standard zipfile.ZipFile class, which implements different iteration logic and is therefore unaffected.

The vulnerability specifically manifests when using zipfile.Path methods that enumerate archive contents, such as namelist() and iterdir(). The malicious archive structure exploits assumptions in the path traversal and entry enumeration logic.

Attack Vector

An attacker can exploit this vulnerability by supplying a maliciously crafted zip archive to a vulnerable application. The attack requires network access to deliver the payload but needs no authentication or special privileges. The exploitation path involves:

1. Crafting a zip archive with specific structural characteristics that trigger the infinite loop
2. Submitting the malicious archive to a target application that processes it using zipfile.Path
3. The application enters an infinite loop when iterating over archive entries, consuming CPU resources
4. The target service becomes unresponsive, achieving denial of service

The vulnerability triggers during both metadata reading operations (such as listing file names) and content extraction, making it exploitable in various application contexts. Programs that do not handle user-controlled zip archives are not affected, as the attack requires the ability to supply malicious input.

Detection Methods for CVE-2024-8088

Indicators of Compromise

• Processes using zipfile.Path showing abnormally high CPU utilization without completing operations
• Python application workers becoming unresponsive when processing zip file uploads
• Timeout errors or hung processes in services that handle zip archive extraction
• Unusual patterns in uploaded zip files with malformed entry structures

Detection Strategies

• Monitor for Python processes with sustained 100% CPU utilization during zip file processing
• Implement application-level timeouts for zip archive operations to detect potential exploitation attempts
• Review application logs for repeated timeout events when handling specific zip file uploads
• Deploy file analysis tools to inspect incoming zip archives for malformed entry structures

Monitoring Recommendations

• Configure process monitoring to alert on Python processes exceeding CPU thresholds during file operations
• Implement request tracing to correlate hung processes with specific uploaded files
• Set up resource quotas and watchdog processes for services handling user-uploaded archives
• Enable detailed logging for zip file processing operations to identify problematic files

How to Mitigate CVE-2024-8088

Immediate Actions Required

• Update CPython to the latest patched version that addresses this vulnerability
• Audit applications for usage of zipfile.Path with user-controlled input and consider switching to zipfile.ZipFile where possible
• Implement timeouts around zip file processing operations to prevent indefinite hangs
• Restrict or validate zip file uploads before processing with zipfile.Path methods

Patch Information

The Python Software Foundation has released patches addressing this vulnerability across multiple Python versions. Multiple commits have been issued to the CPython repository to resolve this issue. Organizations should update to patched Python versions as soon as possible. For detailed patch information, refer to the Python Security Announcement and review the GitHub Pull Request #122906 for technical details.

Additional advisories have been issued by NetApp and Debian LTS for affected distributions.

Workarounds

• Use zipfile.ZipFile instead of zipfile.Path for processing untrusted zip archives, as the former is unaffected
• Implement process-level timeouts using signals or threading to terminate long-running zip operations
• Run zip file processing in isolated worker processes with resource limits to contain potential denial of service
• Validate and pre-screen zip files before processing using external tools that are not vulnerable to this issue

# Example: Implement processing timeout for zip operations
# Use timeout command to limit execution time
timeout 30s python process_zip.py user_uploaded.zip

# Alternative: Configure resource limits for Python processes
ulimit -t 60  # Set CPU time limit in seconds
python process_zip.py user_uploaded.zip