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CVE-2021-3733

6.5 · MEDIUM

There's a flaw in urllib's AbstractBasicAuthHandler class.

Published Mar 10, 2022CWE-400EPSS 4.80%

Overview

CVE-2021-3733 is a medium-severity vulnerability. It was published on March 10, 2022 and has a CVSS 3.1 base score of 6.5 (MEDIUM).

This vulnerability has a CVSS 3.1 base score of 6.5, rated MEDIUM. It can be exploited remotely over the network. Some level of privileges is required for exploitation.

Technical description

There's a flaw in urllib's AbstractBasicAuthHandler class. An attacker who controls a malicious HTTP server that an HTTP client (such as web browser) connects to, could trigger a Regular Expression Denial of Service (ReDOS) during an authentication request with a specially crafted payload that is sent by the server to the client. The greatest threat that this flaw poses is to application availability.

Remediation

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

References

Refbugs.python.org/issue43075Refbugzilla.redhat.com/show_bug.cgi?id=1995234GitHubgithub.com/python/cpython/commit/7215d1ae25525c92b026166f9d5cac85fbGitHubgithub.com/python/cpython/pull/24391Reflists.debian.org/debian-lts-announce/2023/05/msg00024.htmlReflists.debian.org/debian-lts-announce/2023/06/msg00039.htmlRefsecurity.netapp.com/advisory/ntap-20220407-0001/Refubuntu.com/security/CVE-2021-3733Refbugs.python.org/issue43075Refbugzilla.redhat.com/show_bug.cgi?id=1995234

How CyberStrike helps

Frequently asked questions

What is CVE-2021-3733?

CVE-2021-3733 is a medium-severity vulnerability. It was published on March 10, 2022 and has a CVSS 3.1 base score of 6.5 (MEDIUM).

How severe is CVE-2021-3733?

This vulnerability has a CVSS 3.1 base score of 6.5, rated MEDIUM. It can be exploited remotely over the network. Some level of privileges is required for exploitation.

How do I fix or remediate CVE-2021-3733?

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

How can CyberStrike help with CVE-2021-3733?

CyberStrike is an open-source, AI-augmented pentesting engine. Rather than flag a version number, it tests whether an issue like CVE-2021-3733 is actually reachable in your own applications and APIs, then verifies each finding before reporting it. That tells you if the weakness is a real, exploitable risk in your environment or a false positive you can safely deprioritize.

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