CVE-2021-23393 : Security Advisory and Response

A security vulnerability, known as CVE-2021-23393, affects Flask-Unchained before version 0.9.0. This vulnerability allows an attacker to bypass URL validation and redirect a user to a malicious URL using specially crafted input. The impact is considered medium, with a base score of 5.4.

Understanding CVE-2021-23393

This section will cover what CVE-2021-23393 is and its impact.

What is CVE-2021-23393?

CVE-2021-23393 is classified as an Open Redirect vulnerability in Flask-Unchained. It enables attackers to redirect users to arbitrary URLs.

The Impact of CVE-2021-23393

The vulnerability has a medium level impact, with a base score of 5.4. It requires user interaction to be exploited but does not impact availability.

Technical Details of CVE-2021-23393

Outlined in this section are the technical details of the CVE-2021-23393 vulnerability.

Vulnerability Description

Flask-Unchained before 0.9.0 allows URL validation bypass and redirection to malicious URLs.

Affected Systems and Versions

Systems using Flask-Unchained versions earlier than 0.9.0 are impacted by this vulnerability.

Exploitation Mechanism

An attacker can exploit this vulnerability by providing specific input to the _validate_redirect_url function.

Mitigation and Prevention

In this section, we provide guidance on mitigating and preventing exploitation of CVE-2021-23393.

Immediate Steps to Take

Update Flask-Unchained to version 0.9.0 or later to prevent exploitation of this vulnerability.

Long-Term Security Practices

Regularly update all software dependencies to the latest versions to avoid known security issues.

Patching and Updates

Monitor security advisories and CVE databases for any new information on vulnerabilities affecting Flask-Unchained.