Critical Vulnerability in Python Packages: CVE-2025-8194 - Infinite Loop in Tarfile Module
Summary
UBUNTU-CVE-2025-8194: There is a defect in the CPython “tarfile” module affecting the “TarFile” extraction and entry enumeration APIs. Affects python2.7 versions < 2.7.6-8ubuntu0.6+esm26. Fixed in 2.7.6-8ubuntu0.6+esm26. How to fix ↓
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Background
Python is a widely-used high-level programming language known for its readability and versatility. It is utilized in various applications, from web development to data analysis. The affected packages, including python2.7, python3.4, python3.5, python3.6, python3.7, python3.8, python3.9, python3.10, python3.11, and python3.13, are essential components of the Python ecosystem, providing core functionalities and libraries. This vulnerability affects the tarfile module, which is responsible for reading and writing tar archive files, a common format for file distribution.
Vulnerability Detail
The vulnerability identified as CVE-2025-8194 arises from a defect in the CPython tarfile module, specifically affecting the TarFile extraction and entry enumeration APIs. The flaw allows the processing of tar archives with negative offsets without generating an error, leading to an infinite loop and potential deadlock during the parsing of maliciously crafted tar archives. This could result in denial of service, as the application may become unresponsive when attempting to handle such archives.
How To Fix
Minimum fixed version
2.7.6-8ubuntu0.6+esm26
This is the first release that contains the fix.
sudo apt-get install --only-upgrade python2.7Tip — Not sure which version your app runs? Vulert can match this fix to it. Scan free →
Workaround
As a temporary workaround, users can mitigate the risk by avoiding the extraction of untrusted tar archives. Additionally, a patch can be applied after importing the tarfile module to prevent the infinite loop. The following code snippet demonstrates how to implement the patch:
import tarfile
def patched_open(name, mode='r', **kwargs):
# Custom implementation to handle negative offsets
return tarfile.TarFile.open(name, mode, **kwargs)
Replace the original open method with the patched one
tarfile.open = patched_open
Conclusion
CVE-2025-8194 poses a significant risk to applications utilizing the affected Python packages due to its potential to cause denial of service. It is crucial for users to update their packages to the patched versions and implement the suggested workarounds to secure their applications against this vulnerability.
See every vulnerability recorded for python2.7 →
FAQ
CVE-2025-8194 is a vulnerability in the Python tarfile module that can lead to an infinite loop and denial of service when processing malicious tar archives.
The vulnerability affects multiple Python versions, including python2.7, python3.4, python3.5, python3.6, python3.7, python3.8, python3.9, python3.10, python3.11, and python3.13.
You can use Vulert's playground at Vulert Scanner to check if your application is affected by this vulnerability without needing to sign up.
The CVSS score for CVE-2025-8194 is 7.5, indicating a high severity level.
If immediate updates are not possible, avoid extracting untrusted tar archives and consider applying the provided workaround to mitigate risks.
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