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CVE-2021-20254

6.8 · MEDIUM

A flaw was found in samba.

Published May 5, 2021CWE-125EPSS 1.62%

Overview

CVE-2021-20254 is a medium-severity vulnerability. It was published on May 5, 2021 and has a CVSS 3.1 base score of 6.8 (MEDIUM).

This vulnerability has a CVSS 3.1 base score of 6.8, rated MEDIUM. It can be exploited remotely over the network. Some level of privileges is required for exploitation.

Technical description

A flaw was found in samba. The Samba smbd file server must map Windows group identities (SIDs) into unix group ids (gids). The code that performs this had a flaw that could allow it to read data beyond the end of the array in the case where a negative cache entry had been added to the mapping cache. This could cause the calling code to return those values into the process token that stores the group membership for a user. The highest threat from this vulnerability is to data confidentiality and integrity.

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

Refbugzilla.redhat.com/show_bug.cgi?id=1949442Reflists.debian.org/debian-lts-announce/2021/05/msg00023.htmlReflists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/3EP2VJ73OVBPVSOSTVOMGIEQA3MWF6F7/Reflists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/ZAF6L2M6CNAJ2YYYGXPWETTW5YLCWTVT/Refsecurity.gentoo.org/glsa/202105-22Refsecurity.netapp.com/advisory/ntap-20210430-0001/Refwww.samba.org/samba/security/CVE-2021-20254.htmlRefbugzilla.redhat.com/show_bug.cgi?id=1949442Reflists.debian.org/debian-lts-announce/2021/05/msg00023.htmlReflists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/3EP2VJ73OVBPVSOSTVOMGIEQA3MWF6F7/

How CyberStrike helps

Frequently asked questions

What is CVE-2021-20254?

CVE-2021-20254 is a medium-severity vulnerability. It was published on May 5, 2021 and has a CVSS 3.1 base score of 6.8 (MEDIUM).

How severe is CVE-2021-20254?

This vulnerability has a CVSS 3.1 base score of 6.8, 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-2021-20254?

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-2021-20254?

CyberStrike is an open-source, AI-augmented pentesting engine. Rather than flag a version number, it tests whether an issue like CVE-2021-20254 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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