CVE-2025-26699: Django Denial-of-Service Vulnerability Due to Resource Allocation Issues

Background

Django is a high-level Python web framework that encourages rapid development and clean, pragmatic design. It provides a robust set of features for building web applications, including an ORM, routing, templating, and security features. However, certain methods within Django, such as django.utils.text.wrap() and the wordwrap template filter, are susceptible to denial-of-service attacks when processing excessively long strings, leading to potential resource exhaustion.

Vulnerability Detail

An issue was discovered in Django versions 4.2 before 4.2.20, 5.0 before 5.0.13, and 5.1 before 5.1.7. The vulnerability arises from the django.utils.text.wrap() method and the wordwrap template filter, which do not impose limits on the length of strings they process. This oversight can be exploited by attackers to send very long strings, potentially leading to a denial-of-service condition as the application consumes excessive resources while attempting to handle these inputs.

pip install --upgrade "django==6.1.2"

Workaround

As a temporary workaround, you can implement input validation to restrict the length of strings processed by the wrap() method and wordwrap template filter. For example, you can create a custom function that checks the length of the input string before passing it to these methods. Here is a sample code snippet:

def safe_wrap(text, width):
    if len(text) > 1000:  # Limit string length to 1000 characters
        raise ValueError('Input string is too long')
    return django.utils.text.wrap(text, width)

Conclusion

The Django vulnerability CVE-2025-26699 poses a risk of denial-of-service attacks due to improper handling of long strings in specific methods. It is crucial to update to the latest patched versions to mitigate this risk. Implementing input validation can serve as a temporary measure until the update is completed.

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FAQ