An issue was discovered in urllib3 before 1.26.5. When provided with a URL containing many @ characters in the authority component, the authority regular expression exhibits catastrophic backtracking, causing a denial of service if a URL were passed as a parameter or redirected to via an HTTP redirect.
CVE-2021-33503 - High Severity Vulnerability
Vulnerable Library - urllib3-1.25.8-py2.py3-none-any.whl
HTTP library with thread-safe connection pooling, file post, and more.
Library home page: https://files.pythonhosted.org/packages/e8/74/6e4f91745020f967d09332bb2b8b9b10090957334692eb88ea4afe91b77f/urllib3-1.25.8-py2.py3-none-any.whl
Path to dependency file: /requirements.txt
Path to vulnerable library: /requirements.txt,/requirements.txt
Dependency Hierarchy: - requests-2.23.0-py2.py3-none-any.whl (Root Library) - :x: **urllib3-1.25.8-py2.py3-none-any.whl** (Vulnerable Library)
Found in HEAD commit: 14c8156ef390c86cf51dfd1594dcfca33897712b
Found in base branch: master
Vulnerability Details
An issue was discovered in urllib3 before 1.26.5. When provided with a URL containing many @ characters in the authority component, the authority regular expression exhibits catastrophic backtracking, causing a denial of service if a URL were passed as a parameter or redirected to via an HTTP redirect.
Publish Date: 2021-06-29
URL: CVE-2021-33503
CVSS 3 Score Details (7.5)
Base Score Metrics: - Exploitability Metrics: - Attack Vector: Network - Attack Complexity: Low - Privileges Required: None - User Interaction: None - Scope: Unchanged - Impact Metrics: - Confidentiality Impact: None - Integrity Impact: None - Availability Impact: High
For more information on CVSS3 Scores, click here.Suggested Fix
Type: Upgrade version
Origin: https://github.com/urllib3/urllib3/security/advisories/GHSA-q2q7-5pp4-w6pg
Release Date: 2021-06-29
Fix Resolution (urllib3): 1.26.5
Direct dependency fix Resolution (requests): 2.25.0
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