Cross-Site Scripting (XSS) Vulnerability in Mistune Package
Summary
CVE-2017-16876: Cross-site scripting (XSS) vulnerability in the _keyify function in mistune.py in Mistune before 0.8.1 allows remote attackers to inject arbitrary web script or HTML by leveraging failure to escape the "key" argument. Affects mistune across 2 version ranges.
< 0.8.1-1
< 5f06d724bc05580e7f203db2d4a4905fc1127f98
Fixed in 0.8.1-1. How to fix ↓
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Background
Mistune is a fast and efficient Markdown parser for Python, widely used for converting Markdown text into HTML. It is known for its speed and ease of use, making it a popular choice among developers. However, prior to version 0.8.1, Mistune had a critical vulnerability that allowed attackers to exploit the _keyify function, leading to potential XSS attacks.
Vulnerability Detail
The vulnerability, identified as CVE-2017-16876, arises from the failure of the _keyify function in mistune.py to properly escape the 'key' argument. This oversight allows remote attackers to inject arbitrary web scripts or HTML into web pages viewed by other users. The implications of this vulnerability can be severe, as it may lead to unauthorized actions being performed on behalf of users, data theft, or other malicious activities.
How To Fix
Minimum fixed version
0.8.1-1
This is the first release that contains the fix.
sudo apt-get install --only-upgrade mistuneTip — Not sure which version your app runs? Vulert can match this fix to it. Scan free →
Workaround
If upgrading is not immediately possible, consider sanitizing user inputs and escaping outputs in your application to prevent XSS attacks. This can be done using libraries such as 'bleach' in Python, which allows you to clean and escape HTML content effectively.
Conclusion
The CVE-2017-16876 vulnerability in the Mistune package poses a significant risk due to its potential for XSS attacks. It is crucial for users of Mistune to upgrade to version 0.8.1 or later to ensure their applications are secure. Additionally, implementing input sanitization can provide an extra layer of protection.
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FAQ
CVE-2017-16876 is a cross-site scripting (XSS) vulnerability in the Mistune package that allows attackers to inject malicious scripts into web pages.
You can use the Vulert playground at Vulert Scanner to check if your application is affected by this vulnerability without needing to sign up.
The vulnerability can lead to unauthorized actions, data theft, and other malicious activities, compromising user security.
Yes, you can sanitize user inputs and escape outputs using libraries like 'bleach' to prevent XSS attacks.
The CVSS score of this vulnerability is 6.1, indicating a medium severity level.
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