Cross-Site Scripting (XSS) Vulnerability in Python Werkzeug Package
Summary
CVE-2016-10516: Cross-site scripting (XSS) vulnerability in the render_full function in debug/tbtools.py in the debugger in Pallets Werkzeug before 0.11.11 (as used in Pallets Flask and other products) allows remote attackers to inject... Affects python-werkzeug across 2 version ranges.
< 0.11.11+dfsg1-1
< 938a331ddb0c7009f4286e962f8a9c1ebad62be2
Fixed in 0.11.11+dfsg1-1. How to fix ↓
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Background
Python Werkzeug is a comprehensive WSGI utility library for Python that provides various tools for building web applications. It is widely used in frameworks like Flask and is known for its flexibility and ease of use. However, prior to version 0.11.11, Werkzeug contained a vulnerability in its debugger that allowed attackers to inject arbitrary web scripts or HTML through exception messages, posing a significant security risk.
Vulnerability Detail
The vulnerability, identified as CVE-2016-10516, originates from the render_full function in the debug/tbtools.py file within the Werkzeug debugger. This cross-site scripting (XSS) flaw enables remote attackers to exploit the application by injecting malicious scripts into fields that display exception messages. If successful, this could lead to unauthorized actions being performed on behalf of users, data theft, or session hijacking. The vulnerability affects all versions of Werkzeug prior to 0.11.11.
How To Fix
Minimum fixed version
0.11.11+dfsg1-1
This is the first release that contains the fix.
sudo apt-get install --only-upgrade python-werkzeugTip — Not sure which version your app runs? Vulert can match this fix to it. Scan free →
Workaround
If immediate upgrading is not feasible, consider disabling the debugger in production environments to mitigate the risk of exploitation. This can be done by setting the debug flag to false in your application configuration.
Conclusion
The CVE-2016-10516 vulnerability in the Python Werkzeug package poses a significant risk through cross-site scripting. It is crucial for developers to upgrade to the latest version to safeguard their applications against potential attacks. Utilizing tools like Vulert can help monitor and alert for such vulnerabilities in real-time.
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FAQ
CVE-2016-10516 is a cross-site scripting (XSS) vulnerability found in the Python Werkzeug package that allows attackers to inject malicious scripts via exception messages.
You can use the Vulert playground at Vulert Scanner to check if your application is affected by this vulnerability without any signup.
Exploitation of this vulnerability can lead to unauthorized actions, data theft, and session hijacking, compromising user security.
All versions of Werkzeug prior to 0.11.11 are affected by this vulnerability.
The best way to protect your application is to upgrade Werkzeug to version 0.11.11 or later. Additionally, disable the debugger in production environments.
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