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Vulnerability Details : CVE-2021-33503

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 Last Update Date : 2023-01-24
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- CVSS Scores & Vulnerability Types

CVSS Score
Confidentiality Impact None (There is no impact to the confidentiality of the system.)
Integrity Impact None (There is no impact to the integrity of the system)
Availability Impact Partial (There is reduced performance or interruptions in resource availability.)
Access Complexity Low (Specialized access conditions or extenuating circumstances do not exist. Very little knowledge or skill is required to exploit. )
Authentication Not required (Authentication is not required to exploit the vulnerability.)
Gained Access None
Vulnerability Type(s) Denial Of Service
CWE ID 400

- Related OVAL Definitions

Title Definition Id Class Family
RHSA-2021:4160: python39:3.9 and python39-devel:3.9 security update (Moderate) oval:com.redhat.rhsa:def:20214160 unix
RHSA-2021:4162: python38:3.8 and python38-devel:3.8 security update (Moderate) oval:com.redhat.rhsa:def:20214162 unix
OVAL (Open Vulnerability and Assessment Language) definitions define exactly what should be done to verify a vulnerability or a missing patch. Check out the OVAL definitions if you want to learn what you should do to verify a vulnerability.

- Products Affected By CVE-2021-33503

# Product Type Vendor Product Version Update Edition Language
1 OS Fedoraproject Fedora 33 * * * Version Details Vulnerabilities
2 OS Fedoraproject Fedora 34 * * * Version Details Vulnerabilities
3 Application Oracle Enterprise Manager Ops Center * * * Version Details Vulnerabilities
4 Application Oracle Instantis Enterprisetrack 17.1 * * * Version Details Vulnerabilities
5 Application Oracle Instantis Enterprisetrack 17.2 * * * Version Details Vulnerabilities
6 Application Oracle Instantis Enterprisetrack 17.3 * * * Version Details Vulnerabilities
7 Application Oracle Zfs Storage Appliance Kit 8.8 * * * Version Details Vulnerabilities
8 Application Python Urllib3 * * * * Version Details Vulnerabilities

- Number Of Affected Versions By Product

Vendor Product Vulnerable Versions
Fedoraproject Fedora 2
Oracle Enterprise Manager Ops Center 1
Oracle Instantis Enterprisetrack 3
Oracle Zfs Storage Appliance Kit 1
Python Urllib3 1

- References For CVE-2021-33503
GENTOO GLSA-202107-36[email protected]/message/6SCV7ZNAHS3E6PBFLJGENCDRDRWRZZ6W/
FEDORA FEDORA-2021-9c5f3b8aae[email protected]/message/FMUGWEAUYGGHTPPXT6YBD53WYXQGVV73/

- Metasploit Modules Related To CVE-2021-33503

There are not any metasploit modules related to this CVE entry (Please visit for more information)

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