Urllib3
CVE-2023-43804
HIGH
Vulnerability Assessment
| Weakness |
CWE
OWASP Top 10:2025
A01:2025 - Broken Access Control
ASVS 5.0
V14 - Data Protection Data exposure prevention
MITRE ATT&CK
2 techniques across 2 tactics: Collection, Discovery The technique list with ATT&CK links and the kill-chain view is part of the Basic plan and up. |
| Impact | CVSS score of 8.1 (HIGH). Attack characteristics: network attack vector, low complexity, low privileges required, no user interaction not required. |
| Exploit ScenarioDerived | A remote attacker could access sensitive data that should not be disclosed by sending crafted requests to the affected application. |
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Alert meAnalysisAI
urllib3 is a user-friendly HTTP client library for Python. Rated high severity (CVSS 8.1), this vulnerability is remotely exploitable, low attack complexity. This Exposure of Sensitive Information vulnerability could allow attackers to access sensitive data that should not be disclosed.
RemediationAI
A vendor patch is available. Apply the latest security update as soon as possible. Minimize information in error messages, implement proper access controls, encrypt sensitive data at rest and in transit.
Affected Packages
Source: OSV (Open Source Vulnerabilities)
Affects your stack
Affects 1 package in pypi
Checking this CVE against your own stacks and servers is part of the Basic plan and up.
Technical ContextAI · show details
This vulnerability is classified as Exposure of Sensitive Information (CWE-200), which allows attackers to access sensitive data that should not be disclosed. urllib3 is a user-friendly HTTP client library for Python. urllib3 doesn't treat the Cookie HTTP header special or provide any helpers for managing cookies over HTTP, that is the responsibility of the user. However, it is possible for a user to specify a Cookie header and unknowingly leak information via HTTP redirects to a different origin if that user doesn't disable redirects explicitly. This issue has been patched in urllib3 version 1.26.17 or 2.0.5. Affected products include: Python Urllib3, Debian Debian Linux, Fedoraproject Fedora. Version information: version 1.26.17.
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- Exploit and PoC references, threat intelligence from 22 sources
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Severity by source
AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N
Primary rating from NVD · only source for this CVE.
CVSS VectorNVD
DescriptionNVD
urllib3 is a user-friendly HTTP client library for Python. urllib3 doesn't treat the Cookie HTTP header special or provide any helpers for managing cookies over HTTP, that is the responsibility of the user. However, it is possible for a user to specify a Cookie header and unknowingly leak information via HTTP redirects to a different origin if that user doesn't disable redirects explicitly. This issue has been patched in urllib3 version 1.26.17 or 2.0.5.
Blast Radius
ecosystem impact- 11 pypi packages depend on urllib3 (9 direct, 3 indirect)
Ecosystem-wide dependent count for version 2.0.0.
Threat Intelligence Overview
How this decision was reached
The engine reads each signal below and applies a fixed list of rules from top to bottom. The first rule that matches sets the recommended action – like a statement, every line is shown.
What every action level means
SSVC AssessmentENISA
Priority Score
Attack Technique
Information disclosure occurs when an application unintentionally exposes sensitive data that aids attackers in reconnaissance or directly compromises security.
Affected Products (CPE)NVD
urllib3 is a user-friendly HTTP client library for Python. Rated medium severity (CVSS 6.5), this vulnerability is remot
In the urllib3 library through 1.24.1 for Python, CRLF injection is possible if the attacker controls the request parame
urllib3 before version 1.23 does not remove the Authorization HTTP header when following a cross-origin redirect (i.e.,
urllib3 is a user-friendly HTTP client library for Python. Prior to 2.5.0, it is possible to disable redirects for all r
Unbounded memory allocation in urllib3 (1.10.3 through 2.7.x) lets a malicious or machine-in-the-middle HTTP server exha
Resource-exhaustion denial of service in urllib3 1.24 through 2.5.x allows a malicious or attacker-controlled HTTP serve
A decompression-bomb denial-of-service flaw in the urllib3 Python HTTP client library (versions 1.0 through 2.5.x, fixed
Uncontrolled resource consumption in the Python urllib3 HTTP client library (versions 1.22 through 2.6.2) lets a malicio
Certificate validation bypass in urllib3 1.26.0 through 2.7.x allows a man-in-the-middle attacker who can impersonate th
An issue was discovered in urllib3 before 1.26.5. Rated high severity (CVSS 7.5), this vulnerability is remotely exploit
The _encode_invalid_chars function in util/url.py in the urllib3 library 1.25.2 through 1.25.7 for Python allows a denia
The urllib3 library before 1.24.2 for Python mishandles certain cases where the desired set of CA certificates is differ
NVD
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EPSS
GitHub
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