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CVE-2021-33503

Good to know:

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Date: June 29, 2021

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.

Language: Python

Severity Score

Related Resources (15)

https://github.com/pypa/advisory-database/tree/main/vulns/urllib3/PYSEC-2021-108.yaml
https://github.com/urllib3/urllib3/commit/2d4a3fee6de2fa45eb82169361918f759269b4ec
https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/FMUGWEAUYGGHTPPXT6YBD53WYXQGVV73
https://access.redhat.com/security/cve/CVE-2021-33503
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/6SCV7ZNAHS3E6PBFLJGENCDRDRWRZZ6W/
https://github.com/urllib3/urllib3
https://security.gentoo.org/glsa/202107-36
https://github.com/urllib3/urllib3/security/advisories/GHSA-q2q7-5pp4-w6pg
https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/6SCV7ZNAHS3E6PBFLJGENCDRDRWRZZ6W
https://github.com/urllib3/urllib3/commit/5b047b645f5f93900d5e2fc31230848c25eb1f5f#diff-52026d639119bf1e0364836b4e8a18bd9ed3c95c6ba39b26534a5057a65e35bbR65
https://nvd.nist.gov/vuln/detail/CVE-2021-33503
https://www.oracle.com/security-alerts/cpuoct2021.html
https://github.com/advisories/GHSA-q2q7-5pp4-w6pg
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/FMUGWEAUYGGHTPPXT6YBD53WYXQGVV73/
https://www.mend.io/vulnerability-database/CVE-2021-33503

Severity Score

Weakness Type (CWE)

Uncontrolled Resource Consumption ('Resource Exhaustion')

CWE-400

Top Fix

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Upgrade Version

Upgrade to version urllib3 - 1.26.5

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CVSS v3.1

Base Score:
Attack Vector (AV): NETWORK
Attack Complexity (AC): LOW
Privileges Required (PR): NONE
User Interaction (UI): NONE
Scope (S): UNCHANGED
Confidentiality (C): NONE
Integrity (I): NONE
Availability (A): HIGH

CVSS v2

Base Score:
Access Vector (AV): NETWORK
Access Complexity (AC): LOW
Authentication (AU): NONE
Confidentiality (C): NONE
Integrity (I): NONE
Availability (A): PARTIAL
Additional information:

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