CVE-2025-50181 (Medium) Detected In Urllib3-1.24.2-py2.py3-none-any.whl

This article delves into the medium severity vulnerability, identified as CVE-2025-50181, affecting the urllib3 library, specifically version 1.24.2. Urllib3 is a widely used Python HTTP client library known for its thread-safe connection pooling, file posting capabilities, and other essential features. Understanding the nature of this vulnerability, its potential impact, and the recommended fix is crucial for developers and organizations relying on this library.

Vulnerability Details

The vulnerability resides in urllib3 version 1.24.2, a popular Python library that provides a comprehensive set of tools for making HTTP requests. This version is susceptible to a flaw that can be exploited under specific conditions, potentially leading to security breaches. The core issue, as detailed in the National Vulnerability Database (NVD), stems from improper handling of redirects when the library is configured in a certain way. Specifically, if redirects are disabled for all requests by instantiating a PoolManager and specifying retries in a way that disable redirects, applications attempting to mitigate Server-Side Request Forgery (SSRF) or open redirect vulnerabilities at the PoolManager level will remain vulnerable. By default, requests and botocore users are not affected. This vulnerability can allow attackers to potentially bypass security measures intended to prevent unauthorized access or redirection to malicious sites. The severity is rated as medium, indicating a significant risk that needs to be addressed promptly to safeguard systems and data. The vulnerability was discovered and reported, leading to the issuance of CVE-2025-50181 and subsequent efforts to develop a patch and inform the user community about the necessary steps to mitigate the risk.

Vulnerable Library: urllib3-1.24.2-py2.py3-none-any.whl

The vulnerable library in question is urllib3-1.24.2-py2.py3-none-any.whl. Urllib3 is a powerful, user-friendly HTTP client library for Python, designed to simplify making HTTP requests. It offers features like connection pooling, thread safety, and support for various HTTP protocols. This particular version, 1.24.2, has been identified as containing a security vulnerability that could be exploited under certain conditions. The library is available at https://files.pythonhosted.org/packages/df/1c/59cca3abf96f991f2ec3131a4ffe72ae3d9ea1f5894abe8a9c5e3c77cfee/urllib3-1.24.2-py2.py3-none-any.whl, where developers can download and integrate it into their projects. However, due to the identified vulnerability, it is strongly recommended to upgrade to a patched version to ensure the security and integrity of your applications. The library's role in handling HTTP requests makes it a critical component in many Python-based applications, so addressing this vulnerability is essential to prevent potential security breaches. The path to the dependency file and the vulnerable library is /docs/source/requirements.txt, indicating where the library is declared as a dependency within the project.

Dependency Hierarchy

The dependency hierarchy clearly shows that urllib3-1.24.2-py2.py3-none-any.whl is the vulnerable library. This means that any project directly or indirectly relying on this specific version of urllib3 is potentially at risk. It is crucial for developers to understand the dependency structure of their projects to identify and address vulnerabilities effectively. In this case, the highlighted library is the root cause of the security concern, and updating it is the primary step in mitigating the risk. The dependency hierarchy helps in tracing the origin of the vulnerability and ensuring that all affected components are properly patched. The presence of urllib3-1.24.2 in the dependency tree signifies that it is a direct dependency, making it even more critical to address the vulnerability promptly.

Commit and Branch Information

The vulnerability was found in the HEAD commit 3c96bb3a3b67920bb73b4265f804a34eedc9fe77 on the GitHub repository, indicating the specific point in the project's history where the issue was introduced or identified. This information is invaluable for developers and security teams as it allows them to pinpoint the exact changes that might have led to the vulnerability. Additionally, the vulnerability was also found in the base branch, main, which means that the issue is present in the primary development line of the project. This broad presence necessitates immediate action to prevent potential exploitation. The commit hash serves as a unique identifier for the change, enabling developers to examine the code and understand the context of the vulnerability. Knowing the affected branch further helps in planning the remediation efforts and ensuring that all relevant versions of the software are patched.

Vulnerability Details: CVE-2025-50181

CVE-2025-50181 is a critical vulnerability affecting the urllib3 library, a widely used Python HTTP client. This vulnerability, if exploited, could have significant implications for the security of applications that rely on the affected versions of urllib3. Specifically, the vulnerability arises from the library's handling of redirects. When redirects are disabled for all requests by instantiating a PoolManager and specifying retries in a way that disable redirects, applications attempting to mitigate Server-Side Request Forgery (SSRF) or open redirect vulnerabilities at the PoolManager level will remain vulnerable. By default, requests and botocore users are not affected. This means that attackers could potentially bypass security measures intended to prevent unauthorized access or redirection to malicious sites. The Common Vulnerabilities and Exposures (CVE) identifier provides a standardized way to reference this specific security flaw, making it easier for developers and security professionals to track and address the issue. The vulnerability underscores the importance of staying updated with the latest security patches and best practices in software development to protect against potential threats.

Vulnerability Description

The core of the vulnerability lies in how urllib3 handles redirects. When an application attempts to disable redirects at the PoolManager level to mitigate SSRF or open redirect vulnerabilities, a flaw in the library can leave it exposed. This is because the mechanism intended to prevent redirects can be bypassed under certain conditions. Specifically, if redirects are disabled for all requests by instantiating a PoolManager and specifying retries in a way that disable redirects, applications attempting to mitigate Server-Side Request Forgery (SSRF) or open redirect vulnerabilities at the PoolManager level will remain vulnerable. By default, requests and botocore users are not affected. This means that even if developers have taken steps to secure their applications by disabling redirects, the vulnerability can still be exploited if the underlying urllib3 library is not patched. The vulnerability can lead to various security risks, including unauthorized access to internal resources, exposure of sensitive data, and redirection to malicious websites. The issue highlights the importance of thoroughly testing security measures and ensuring that all components of a system are protected against potential vulnerabilities. The impact of this vulnerability can be severe, especially in applications that handle sensitive information or interact with external systems.

Publish Date and URL

This vulnerability was officially published on June 19, 2025, marking the date when the security community was formally made aware of the issue. The timely disclosure of vulnerabilities is crucial for allowing developers and system administrators to take appropriate action to protect their systems. Along with the publication date, a dedicated URL, https://www.mend.io/vulnerability-database/CVE-2025-50181, provides detailed information about CVE-2025-50181. This URL serves as a central resource for understanding the specifics of the vulnerability, its potential impact, and the recommended steps for mitigation. Security advisories, technical write-ups, and discussions about the vulnerability can often be found through this link, making it an essential reference point for those addressing the issue. The URL also helps in tracking the vulnerability's status, including any updates or patches released to address it. Access to comprehensive information is vital for effective vulnerability management and ensuring that systems remain secure.

CVSS 3 Score Details (5.3)

The CVSS 3 score for CVE-2025-50181 is 5.3, which classifies it as a medium severity vulnerability. The Common Vulnerability Scoring System (CVSS) is a standardized method for assessing the severity of security vulnerabilities. A score of 5.3 indicates that the vulnerability poses a moderate risk, requiring attention and remediation efforts. The CVSS score is calculated based on various metrics, including the exploitability of the vulnerability and its potential impact. Understanding the CVSS score helps in prioritizing security efforts and allocating resources effectively. Vulnerabilities with higher scores typically demand more immediate attention due to their potential for greater harm. The CVSS score provides a consistent and objective measure of severity, facilitating communication and collaboration among security professionals. This score serves as a critical indicator for organizations to gauge the level of risk associated with the vulnerability and to implement appropriate countermeasures.

Base Score Metrics

The base score metrics provide a detailed breakdown of the vulnerability's characteristics, which contribute to the overall CVSS score. These metrics are divided into two main categories: Exploitability Metrics and Impact Metrics. Exploitability Metrics assess how easily the vulnerability can be exploited, while Impact Metrics evaluate the potential consequences of a successful exploit. These metrics offer a granular view of the vulnerability, enabling a more precise understanding of its nature and potential impact. The base score metrics are crucial for security professionals in assessing the risk and devising mitigation strategies. By examining these metrics, organizations can better understand the specific aspects of the vulnerability that pose the greatest threat and tailor their response accordingly. These metrics form the foundation of the CVSS score, providing a transparent and objective assessment of the vulnerability's severity.

Exploitability Metrics

The Exploitability Metrics for CVE-2025-50181 provide valuable insights into how easily an attacker can leverage this vulnerability. These metrics include Attack Vector, Attack Complexity, Privileges Required, User Interaction, and Scope. The Attack Vector is Network, indicating that the vulnerability can be exploited remotely over a network, making it more accessible to potential attackers. The Attack Complexity is High, suggesting that exploiting the vulnerability requires specialized conditions or attacker capabilities, reducing the likelihood of widespread exploitation. Privileges Required are Low, meaning that an attacker needs minimal access rights to exploit the vulnerability. User Interaction is None, indicating that no user action is required for the vulnerability to be exploited, increasing the potential for automated attacks. Scope is Unchanged, which means that the vulnerability's impact is limited to the affected component and does not extend to other parts of the system. Understanding these exploitability metrics is crucial for assessing the realistic risk posed by the vulnerability and prioritizing remediation efforts accordingly.

Impact Metrics

The Impact Metrics for CVE-2025-50181 describe the potential consequences of a successful exploit. These metrics include Confidentiality Impact, Integrity Impact, and Availability Impact. For this vulnerability, Confidentiality Impact is High, indicating that there is a significant risk of unauthorized access to sensitive information. Integrity Impact is None, meaning that the vulnerability does not directly lead to the alteration or corruption of data. Availability Impact is also None, suggesting that the vulnerability does not cause disruptions in service or system downtime. The high Confidentiality Impact is a primary concern, as it means that attackers could potentially gain access to confidential data if the vulnerability is exploited. The absence of Integrity and Availability Impacts reduces the overall severity but does not eliminate the need for prompt remediation. Understanding these impact metrics helps in focusing security efforts on protecting the confidentiality of data and preventing unauthorized access.

CVSS 3 Calculator

For more detailed information on CVSS3 Scores, you can refer to the CVSS calculator available at https://www.first.org/cvss/calculator/3.0. The CVSS calculator is a valuable tool for understanding how different metrics contribute to the overall score. It allows users to input specific values for each metric and see how the score changes, providing a deeper insight into the vulnerability's severity. Using the calculator can help in customizing the risk assessment based on specific environmental and operational factors. The CVSS calculator is an essential resource for security professionals and developers who need to perform accurate and comprehensive vulnerability assessments. It ensures that the scoring process is transparent and consistent, facilitating better communication and decision-making.

Suggested Fix

The suggested fix for CVE-2025-50181 is to upgrade to version 2.5.0 of the urllib3 library. This updated version includes a patch that addresses the vulnerability, ensuring that the library handles redirects correctly and prevents potential exploits. Upgrading is the most effective way to mitigate the risk associated with this vulnerability and protect your applications. The upgrade process typically involves updating the library in your project's dependencies and redeploying the application. It is crucial to test the updated version thoroughly to ensure that it resolves the vulnerability and does not introduce any new issues. Staying current with the latest security patches is a fundamental aspect of maintaining a secure software environment. Regularly updating libraries and frameworks helps in safeguarding against known vulnerabilities and minimizing the risk of exploitation.

Fix Details

The recommended fix involves upgrading to urllib3 version 2.5.0. This version specifically addresses the vulnerability identified as CVE-2025-50181, which relates to improper handling of redirects. The upgrade ensures that the library correctly manages redirects, preventing potential security breaches. The fix was released on June 19, 2025, the same date as the vulnerability's publication, indicating a prompt response to the identified issue. The Fix Resolution is 2.5.0, clearly specifying the version that contains the necessary patch. When upgrading, it is important to follow the library's documentation and best practices to ensure a smooth and secure transition. Testing the application after the upgrade is crucial to confirm that the fix is effective and that no new issues have been introduced. This proactive approach to security helps in maintaining the integrity and reliability of the application.

Type and Release Date

The type of fix is an upgrade version, emphasizing that the solution involves moving to a newer release of the urllib3 library. This approach ensures that the vulnerability is addressed and that the application benefits from any other improvements and security enhancements included in the new version. The release date of the fix is June 19, 2025, which aligns with the publication date of the vulnerability. This timely release underscores the importance of promptly addressing security concerns and providing users with the necessary tools to protect their systems. Keeping track of release dates is crucial for maintaining an up-to-date and secure software environment. By staying informed about the latest releases and updates, developers can proactively manage vulnerabilities and ensure the ongoing security of their applications.

Step up Your Open Source Security Game with Mend

Enhance your open source security practices with Mend, a comprehensive solution designed to help you identify and remediate vulnerabilities in your software. Mend offers a range of tools and services to streamline your security efforts, from vulnerability scanning to automated remediation. By integrating Mend into your development workflow, you can proactively address security risks and ensure the integrity of your applications. Discover how Mend can help you strengthen your security posture here. Investing in robust security solutions is essential for protecting your systems and data from potential threats.