CVE-2021-32838 : Security Advisory and Response
Learn about CVE-2021-32838, a vulnerability in flask-restx versions prior to 0.5.1 enabling Regular Expression Denial of Service attacks. Explore the impact, technical details, and mitigation steps.
Flask-RESTX (pypi package flask-restx) before version 0.5.1 is vulnerable to ReDoS (Regular Expression Denial of Service) in email_regex. This can lead to a denial of service attack due to uncontrolled resource consumption.
Understanding CVE-2021-32838
Flask-RESTX is a community-driven fork of Flask-RESTPlus that suffers from a vulnerability in its email_regex module, allowing attackers to exploit it for performing ReDoS attacks.
What is CVE-2021-32838?
This CVE identifies a security vulnerability in flask-restx versions earlier than 0.5.1 that enables attackers to launch Regular Expression Denial of Service attacks by exploiting email_regex.
The Impact of CVE-2021-32838
The impact of this vulnerability is considered high, with a CVSS v3.1 base score of 7.5 (High). Attackers can potentially disrupt the availability of the affected system.
Technical Details of CVE-2021-32838
The vulnerability stems from uncontrolled resource consumption in the affected email_regex module of flask-restx.
Vulnerability Description
flask-restx versions prior to 0.5.1 are susceptible to ReDoS attacks due to inadequate input validation in the email_regex component.
Affected Systems and Versions
Systems using flask-restx versions lower than 0.5.1 are at risk of exploitation by threat actors leveraging ReDoS techniques.
Exploitation Mechanism
Attackers can exploit this vulnerability by crafting malicious inputs that trigger excessive backtracking in the email_regex module.
Mitigation and Prevention
To address CVE-2021-32838, immediate steps include updating flask-restx to version 0.5.1 or newer. Additionally, adopting robust security practices can help mitigate similar vulnerabilities in the future.
Immediate Steps to Take
Update flask-restx to version 0.5.1 or the latest release to patch the ReDoS vulnerability present in email_regex.
Long-Term Security Practices
Regularly monitor for security advisories and apply updates promptly to prevent exploitation of known vulnerabilities in dependencies.
Patching and Updates
Stay informed about security patches and updates for flask-restx to ensure the continued protection of your applications.