Setuptools Security Vulnerability: CVE-2022-40897

by Alex Johnson 50 views

In the realm of software development, security vulnerabilities are a persistent concern, and staying informed about potential threats is crucial for maintaining robust and reliable systems. This article delves into a medium severity security vulnerability detected in setuptools, a critical Python packaging library. We will explore the details of the vulnerability, its potential impact, and the steps you can take to mitigate the risk.

Understanding the Vulnerability

The vulnerability, identified as CVE-2022-40897, affects setuptools versions prior to 65.5.1. It stems from a Regular Expression Denial of Service (ReDoS) issue within the package_index.py file. This flaw can be exploited by remote attackers who can trigger a denial-of-service (DoS) condition by sending specially crafted HTML content within a package or through a custom PackageIndex page. Let's break down the key components of this vulnerability:

  • CVE-2022-40897: This is the unique identifier assigned to this vulnerability in the Common Vulnerabilities and Exposures (CVE) database. This ID allows security professionals and developers to track and reference the vulnerability.
  • Affected Component: The vulnerability resides within setuptools, a widely used library that simplifies the process of packaging and distributing Python projects. It provides tools and utilities for creating Python packages, managing dependencies, and uploading packages to package repositories like PyPI (Python Package Index).
  • Vulnerability Type: The vulnerability is classified as a Regular Expression Denial of Service (ReDoS). ReDoS vulnerabilities occur when a regular expression, used for pattern matching, exhibits extremely poor performance when processing certain input strings. This can lead to excessive CPU consumption and, ultimately, a denial of service.
  • Attack Vector: The vulnerability can be exploited remotely by attackers who can inject malicious HTML content into a package or a custom PackageIndex page. This means that an attacker doesn't need direct access to the system; they can trigger the vulnerability through network requests.
  • Impact: A successful exploitation of this vulnerability can result in a denial-of-service condition. This means that the affected system or application becomes unavailable to legitimate users. In the context of setuptools, this could potentially disrupt the packaging and distribution of Python projects, impacting developers and users alike.

To fully grasp the impact, it's essential to understand how regular expressions work and how ReDoS vulnerabilities arise. Regular expressions are powerful tools for pattern matching, but their performance can vary significantly depending on the complexity of the expression and the input data. In certain cases, a poorly designed regular expression can enter a state of exponential backtracking, where the matching process becomes incredibly slow, consuming excessive CPU resources. This is the core principle behind ReDoS attacks.

Delving Deeper into the Details

To gain a more technical understanding of the vulnerability, let's examine the metadata associated with CVE-2022-40897. The metadata provides valuable insights into the vulnerability's characteristics and severity.

The provided JSON metadata offers a structured representation of the vulnerability's key attributes. Let's dissect this information:

{"vulnerabilityIdentifiers":["CVE-2022-40897"],
"published":"2022-12-23T00:15:13.987",
"lastModified":"2025-11-04T16:15:52.260",
"version":"3.1",
"vectorString":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H",
"baseScore":5.9,
"baseSeverity":"MEDIUM",
"attackVector":"NETWORK",
"attackComplexity":"HIGH",
"privilegesRequired":"NONE",
"userInteraction":"NONE",
"scope":"UNCHANGED",
"confidentialityImpact":"NONE",
"integrityImpact":"NONE",
"availabilityImpact":"HIGH",
"exploitabilityScore":2.2,
"impactScore":3.6,
"weaknesses":["CWE-1333","CWE-1333"]}
  • vulnerabilityIdentifiers: This array confirms the CVE identifier for the vulnerability, which is CVE-2022-40897.
  • published: This field indicates the date and time when the vulnerability was initially published, which was December 23, 2022.
  • lastModified: This field shows the last time the vulnerability information was updated, November 4, 2025.
  • version: This specifies the version of the Common Vulnerability Scoring System (CVSS) used for scoring the vulnerability, which is version 3.1.
  • vectorString: This is a crucial piece of information, representing the CVSS vector string. It provides a concise summary of the vulnerability's characteristics using a specific notation. Let's break down the vector string:
    • CVSS:3.1: Indicates the CVSS version used.
    • AV:N: Attack Vector is Network, meaning the vulnerability can be exploited over a network.
    • AC:H: Attack Complexity is High, suggesting that exploiting the vulnerability requires specialized conditions or attacker capabilities.
    • PR:N: Privileges Required is None, meaning no special privileges are needed to exploit the vulnerability.
    • UI:N: User Interaction is None, indicating that no user interaction is required for exploitation.
    • S:U: Scope is Unchanged, meaning the vulnerability's impact is limited to the affected component.
    • C:N: Confidentiality Impact is None, indicating no compromise of sensitive information.
    • I:N: Integrity Impact is None, meaning no alteration of data integrity.
    • A:H: Availability Impact is High, signifying a significant disruption of service.
  • baseScore: This is the overall CVSS base score, which is 5.9. This score reflects the inherent severity of the vulnerability.
  • baseSeverity: Based on the base score, the vulnerability is classified as MEDIUM severity.
  • attackVector: Reiterates that the attack vector is NETWORK.
  • attackComplexity: Confirms that the attack complexity is HIGH.
  • privilegesRequired: Indicates that no privileges are required to exploit the vulnerability.
  • userInteraction: Specifies that no user interaction is needed for exploitation.
  • scope: States that the scope is UNCHANGED.
  • confidentialityImpact: Highlights that there is no confidentiality impact.
  • integrityImpact: Indicates that there is no integrity impact.
  • availabilityImpact: Emphasizes the HIGH availability impact.
  • exploitabilityScore: This score (2.2) reflects the ease with which the vulnerability can be exploited. A lower score suggests it's harder to exploit.
  • impactScore: This score (3.6) represents the potential impact of a successful exploitation. A higher score indicates a greater impact.
  • weaknesses: This array lists the Common Weakness Enumeration (CWE) identifiers associated with the vulnerability. In this case, it's CWE-1333, which specifically refers to ReDoS vulnerabilities.

The CVSS vector string and the associated scores provide a standardized way to assess the severity and characteristics of the vulnerability. The fact that the attack complexity is high suggests that exploiting this vulnerability requires specialized knowledge and techniques. However, the high availability impact underscores the potential for significant disruption if the vulnerability is successfully exploited.

Mitigation Strategies

Given the potential impact of this vulnerability, it's essential to take proactive steps to mitigate the risk. The primary mitigation strategy is to upgrade to setuptools version 65.5.1 or later. This version includes a fix that addresses the ReDoS vulnerability. Upgrading is a relatively straightforward process and is highly recommended for all users of setuptools.

In addition to upgrading, consider the following security best practices:

  • Regularly Update Dependencies: Keep all your Python packages and dependencies up to date. Security vulnerabilities are often discovered in older versions of software, so staying current is crucial.
  • Dependency Scanning Tools: Utilize dependency scanning tools to automatically identify known vulnerabilities in your project's dependencies. These tools can help you proactively address security risks.
  • Input Validation: Implement robust input validation techniques to prevent the injection of malicious data, such as crafted HTML, into your application. This can help mitigate various types of vulnerabilities, including ReDoS.
  • Web Application Firewalls (WAFs): If your application involves web-based components, consider using a WAF to filter out malicious traffic and prevent attacks.

By implementing these mitigation strategies and staying informed about security vulnerabilities, you can significantly reduce the risk of exploitation and maintain the security and stability of your Python projects.

Conclusion

The security vulnerability in setuptools (CVE-2022-40897) highlights the importance of staying vigilant about potential threats in software dependencies. While the vulnerability has a medium severity rating and a high attack complexity, the potential for denial of service underscores the need for prompt action. Upgrading to setuptools version 65.5.1 or later is the most effective way to mitigate this risk. By adopting security best practices and staying informed, you can safeguard your Python projects and maintain a secure development environment.

For more information on security vulnerabilities and best practices, consider exploring resources like the National Vulnerability Database.