Boto3 Vulnerability: CVE-2025-50181 Alert!

This report details a security vulnerability found in the boto3-1.40.72-py3-none-any.whl library, specifically highlighting a medium-severity issue, CVE-2025-50181, stemming from a transitive dependency on urllib3. Let's dive into the specifics, impact, and potential remediation steps.

Vulnerabilities

The following table summarizes the vulnerability:

Vulnerability	Severity	CVSS	Dependency	Type	Fixed in (boto3 version)	Remediation Possible
CVE-2025-50181	Medium	5.3	urllib3-1.26.20-py2.py3-none-any.whl	Transitive	N/A*	No

*Note: A fix may not be available in a direct dependency. Check the "Details" section for fixes in transitive dependencies.

Details on CVE-2025-50181

This section provides a deep dive into the vulnerability, its potential impact, and suggested fixes.

Vulnerable Library: urllib3-1.26.20-py2.py3-none-any.whl

urllib3 is a powerful and widely-used HTTP client library for Python, known for its thread-safe connection pooling and other advanced features. This vulnerability arises in version 1.26.20. The library's home page can be found here.

The vulnerability exists because, prior to version 2.5.0, it was possible to disable redirects for all requests by instantiating a PoolManager and specifying retries in a way that effectively disabled redirects. While requests and botocore users are generally not affected by default, applications attempting to mitigate Server-Side Request Forgery (SSRF) or open redirect vulnerabilities by disabling redirects at the PoolManager level would remain exposed. This vulnerability has been addressed in urllib3 version 2.5.0.

This issue is a critical concern for applications relying on urllib3 for secure HTTP communications, especially those that have implemented custom redirect policies to prevent SSRF attacks. The ability to bypass these policies could lead to unauthorized access to internal resources, data breaches, or other malicious activities. It is imperative to assess your application's usage of urllib3 and take appropriate action to mitigate this vulnerability.

The path to the dependency file is /examples/iac_approval_workflow/requirements.txt. The vulnerable library is located at /tmp/ws-ua_20251113154545_JGYQAB/python_KHEWJP/202511131547271/env/lib/python3.9/site-packages/urllib3-1.26.20.dist-info.

The dependency hierarchy is as follows:

• boto3-1.40.72-py3-none-any.whl (Root Library)
  • botocore-1.40.72-py3-none-any.whl
    • urllib3-1.26.20-py2.py3-none-any.whl (Vulnerable Library)

This vulnerability was identified in commit 6d8991bd7b4fde0bd9127a1db24e98302c8836a9 and is present in the main branch.

Vulnerability Explanation

urllib3 is a vital HTTP client library for Python, offering features like thread-safe connection pooling and file posting. The vulnerability, CVE-2025-50181, arises from the possibility of disabling redirects for all requests through specific configurations of the PoolManager. While default configurations of requests and botocore are typically unaffected, applications employing redirect disabling at the PoolManager level to defend against SSRF or open redirect vulnerabilities remain at risk. The core of the issue lies in the inadequate enforcement of redirect policies when custom configurations are applied, potentially allowing malicious actors to bypass security measures designed to prevent unauthorized access or redirection to harmful sites. Therefore, careful review of how urllib3 is configured and used is essential to ensure the security of applications.

CVSS 3 Score: 5.3 (Medium)

The CVSS (Common Vulnerability Scoring System) provides a standardized way to assess the severity of vulnerabilities. This vulnerability has a CVSS v3 score of 5.3, indicating a medium severity. This score is derived from the following metrics:

• Attack Vector: Network (AV:N)
• Attack Complexity: High (AC:H)
• Privileges Required: Low (PR:L)
• User Interaction: None (UI:N)
• Scope: Unchanged (S:U)
• Confidentiality Impact: High (C:H)
• Integrity Impact: None (I:N)
• Availability Impact: None (A:N)

The high confidentiality impact suggests that successful exploitation could lead to the disclosure of sensitive information. While integrity and availability are not directly impacted, the confidentiality breach can have significant consequences depending on the nature of the data exposed. The high attack complexity implies that exploitation requires specific conditions to be met, but the low privileges required and lack of user interaction make it easier for attackers to potentially exploit the vulnerability. Therefore, even though the attack complexity is high, the potential impact warrants careful attention and remediation.

For more details on CVSS scores, refer to the FIRST website.

Suggested Remediation

The recommended solution is to upgrade to urllib3 version 2.5.0 or later. This version includes a patch that addresses the vulnerability by ensuring that redirect policies are consistently enforced, regardless of the PoolManager configuration. Upgrading the library will prevent potential bypasses of security measures and protect against SSRF or open redirect attacks.

To upgrade, use the following command:

pip install 'urllib3>=2.5.0'

Ensure that all dependencies that rely on urllib3 are compatible with the new version to avoid any compatibility issues. After upgrading, thoroughly test your application to confirm that the fix has been successfully applied and that no new issues have been introduced. Regularly monitoring for security updates and applying them promptly is a critical part of maintaining a secure environment.

• Type: Upgrade version
• Release Date: 2025-06-19
• Fix Resolution: urllib3 - 2.5.0

Summary and Conclusion

In summary, the boto3-1.40.72-py3-none-any.whl library is affected by a medium-severity vulnerability (CVE-2025-50181) due to its dependency on urllib3. This vulnerability could allow attackers to bypass redirect policies, potentially leading to SSRF attacks or open redirects. To mitigate this risk, it is strongly recommended to upgrade to urllib3 version 2.5.0 or later.

Always ensure that your dependencies are up to date and that you are following security best practices to protect your applications from potential threats. Regularly audit your dependencies and apply necessary patches to maintain a secure environment.

For more information on urllib3 and its security practices, visit the urllib3 documentation.