CVE-2021-20251

Name: CVE-2021-20251
Creator: NVD / NIST
Published: 2023-03-06T23:15:10.387+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

MEDIUMCVSS 5.9/10EPSS 0.76%

Last modified Jun 17, 2026

CVE-2021-20251 is a medium-severity vulnerability rated 5.9/10 on the CVSS scale. A flaw was found in samba. A race condition in the password lockout code may lead to the risk of brute force attacks being successful if special conditions are met.. EPSS estimates a 0.76% chance of exploitation in the next 30 days.

Description

A flaw was found in samba. A race condition in the password lockout code may lead to the risk of brute force attacks being successful if special conditions are met.

Metrics

CVSS 3.1

5.9/10

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N

EPSS Probability

0.76%

50.5th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

Affected Software

Vendor	Product	Versions
Samba	Samba	>= 4.1.0, < 4.16.8
Samba	Samba	>= 4.17.0, < 4.17.4
Fedoraproject	Fedora	37

References

https://bugzilla.redhat.com/show_bug.cgi?id=1929800Issue Tracking, Third Party Advisory
https://bugzilla.samba.org/show_bug.cgi?id=14611Exploit, Issue Tracking, Third Party Advisory
https://security.gentoo.org/glsa/202309-06
https://security.netapp.com/advisory/ntap-20230331-0005/Third Party Advisory
https://bugzilla.redhat.com/show_bug.cgi?id=1929800Issue Tracking, Third Party Advisory
https://bugzilla.samba.org/show_bug.cgi?id=14611Exploit, Issue Tracking, Third Party Advisory
https://security.gentoo.org/glsa/202309-06
https://security.netapp.com/advisory/ntap-20230331-0005/Third Party Advisory

Timeline

Published: Mar 6, 2023
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2021-20251?

A flaw was found in samba. A race condition in the password lockout code may lead to the risk of brute force attacks being successful if special conditions are met.

How severe is CVE-2021-20251?

CVE-2021-20251 has a CVSS score of 5.9/10 (MEDIUM severity). The EPSS model estimates a 0.76% probability of exploitation in the next 30 days.

How do I fix CVE-2021-20251?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2021-20251?

Run a free Strix scan to check your systems for this vulnerability.

Scan your code now

Source: NVD / NIST