Critical Security Update for python3-jinja2: Jinja Sandbox Breakout Vulnerability
Summary
ALSA-2025:3406: Important: python-jinja2 security update. Affects python3-jinja2 versions < 2.11.3-8.el9_5. Fixed in 2.11.3-8.el9_5. How to fix ↓
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Background
Python3-jinja2 is a templating engine for Python, widely used for rendering dynamic web pages. It allows developers to create templates that can be populated with data, making it a powerful tool for web development. However, vulnerabilities in jinja2 can lead to severe security issues, such as unauthorized access to sensitive data or system commands, particularly through its sandboxing features.
Vulnerability Detail
The vulnerability identified as CVE-2025-27516 pertains to a sandbox breakout in jinja2. This issue arises when the 'attr' filter is used to select the 'format' method, potentially allowing an attacker to execute arbitrary code outside the intended sandbox environment. The ramifications of this vulnerability can be significant, as it may enable unauthorized access to system resources or sensitive data, compromising the integrity and security of applications utilizing this package.
How To Fix
Minimum fixed version
2.11.3-8.el9_5
This is the first release that contains the fix.
sudo dnf update python3-jinja2Tip — Not sure which version your app runs? Vulert can match this fix to it. Scan free →
Workaround
As a temporary workaround, developers can avoid using the 'attr' filter in their templates until the package is updated. This can help mitigate the risk of exploitation while waiting for the official patch.
Conclusion
The python3-jinja2 package has a critical vulnerability (CVE-2025-27516) that allows for sandbox breakout, which could lead to severe security risks. It is crucial to update to the patched version 2.11.3-8.el9_5 to ensure the security of applications. Temporary workarounds are available, but the best course of action is to apply the update as soon as possible.
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FAQ
CVE-2025-27516 is a security vulnerability in the python3-jinja2 package that allows for sandbox breakout through the 'attr' filter, potentially leading to unauthorized code execution.
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 access to sensitive data and system commands, posing a significant risk to the security of applications using jinja2.
Yes, the patched version of python3-jinja2 is 2.11.3-8.el9_5. Updating to this version will resolve the vulnerability.
If an immediate update is not possible, avoid using the 'attr' filter in your templates as a temporary workaround to mitigate the risk.
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