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CVE-2021-21317

5.3 · MEDIUM

uap-core in an open-source npm package which contains the core of BrowserScope's original user agent string parser.

Published Feb 16, 2021CWE-400EPSS 2.52%

Overview

CVE-2021-21317 is a medium-severity vulnerability. It was published on February 16, 2021 and has a CVSS 3.1 base score of 5.3 (MEDIUM).

This vulnerability has a CVSS 3.1 base score of 5.3, rated MEDIUM. It can be exploited remotely over the network. No authentication or special privileges are required for exploitation.

Technical description

uap-core in an open-source npm package which contains the core of BrowserScope's original user agent string parser. In uap-core before version 0.11.0, some regexes are vulnerable to regular expression denial of service (REDoS) due to overlapping capture groups. This allows remote attackers to overload a server by setting the User-Agent header in an HTTP(S) request to maliciously crafted long strings. This is fixed in version 0.11.0. Downstream packages such as uap-python, uap-ruby etc which depend upon uap-core follow different version schemes.

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

GitHubgithub.com/ua-parser/uap-core/commit/dc9925d458214cfe87b93e35346980612f6ae96cGitHubgithub.com/ua-parser/uap-core/security/advisories/GHSA-p4pj-mg4r-x6v4Refwww.npmjs.com/package/uap-coreGitHubgithub.com/ua-parser/uap-core/commit/dc9925d458214cfe87b93e35346980612f6ae96cGitHubgithub.com/ua-parser/uap-core/security/advisories/GHSA-p4pj-mg4r-x6v4Refwww.npmjs.com/package/uap-core

How CyberStrike helps

Frequently asked questions

What is CVE-2021-21317?

CVE-2021-21317 is a medium-severity vulnerability. It was published on February 16, 2021 and has a CVSS 3.1 base score of 5.3 (MEDIUM).

How severe is CVE-2021-21317?

This vulnerability has a CVSS 3.1 base score of 5.3, rated MEDIUM. It can be exploited remotely over the network. No authentication or special privileges are required for exploitation.

How do I fix or remediate CVE-2021-21317?

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-2021-21317?

CyberStrike is an open-source, AI-augmented pentesting engine. Rather than flag a version number, it tests whether an issue like CVE-2021-21317 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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