CVE-2021-20251

MEDIUMNVD 5.95.9—

5.9

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.

CVSS v3: 5.9
EG Score: 5.9(medium)
EPSS: 44.8%
KEV: Not listed

Published

March 6, 2023

Last Modified

November 21, 2024

References (8)

secalert@redhathttps://bugzilla.redhat.com/show_bug.cgi?id=1929800
secalert@redhathttps://bugzilla.samba.org/show_bug.cgi?id=14611
secalert@redhathttps://security.gentoo.org/glsa/202309-06
secalert@redhathttps://security.netapp.com/advisory/ntap-20230331-0005/
af854a3a-2127-422b-91ae-364da2661108https://bugzilla.redhat.com/show_bug.cgi?id=1929800
af854a3a-2127-422b-91ae-364da2661108https://bugzilla.samba.org/show_bug.cgi?id=14611
af854a3a-2127-422b-91ae-364da2661108https://security.gentoo.org/glsa/202309-06
af854a3a-2127-422b-91ae-364da2661108https://security.netapp.com/advisory/ntap-20230331-0005/

Patch Availability(1)

Vendor / Ecosystem	Fixed in / Patch	Released	Source
ubuntu	ctdb (2:4.16.8+dfsg-0ubuntu1) @ kinetic	2026-05-25	ubuntu

Patches are aggregated from vendor advisories (Red Hat, Microsoft, Cisco, GitHub) and package ecosystems (OSV, GHSA). Multiple rows for the same upstream release have been deduplicated.

Weakness Classification(1)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

CWE-362Concurrent Execution using Shared Resource with Improper Synchronization (Race Condition)

All Vendor Advisories

(2)

Every vendor that published an advisory referencing this CVE — pulled from our cve_vendor_advisories aggregation. Click any row for the vendor's original advisory page.

Data Freshness Timeline

(refreshed 10× in last 7d / 20× in last 30d)

Every time one of our enrichment pipelines (NVD, MITRE cvelistV5, EPSS, CISA KEV, GHSA, OSV, vendor advisories) ran against this CVE. Most recent first.

2026-06-04 13:10 UTCepss_batch
2026-06-02 20:11 UTCepss_batch
2026-06-02 20:11 UTCepss_batch
2026-06-01 13:50 UTCepss_batch
2026-06-01 13:50 UTCepss_batch
2026-05-31 22:29 UTCepss_batch
2026-05-31 22:29 UTCepss_batch
2026-05-31 00:15 UTCepss_batch
2026-05-31 00:15 UTCepss_batch
2026-05-29 13:42 UTCepss_batch
2026-05-28 13:43 UTCepss_batch
2026-05-28 13:43 UTCepss_batch
2026-05-27 13:39 UTCepss_batch
2026-05-26 13:42 UTCepss_batch
2026-05-26 13:42 UTCepss_batch
2026-05-26 07:17 UTCepss_batch
2026-05-26 07:17 UTCepss_batch
2026-05-25 05:42 UTCEG score recompute
2026-05-25 05:42 UTCVendor advisory
2026-05-25 05:42 UTCGHSA enrichment

Frequently asked(5)

What is CVE-2021-20251?

CVE-2021-20251 is a medium vulnerability published on March 6, 2023. 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.

When was CVE-2021-20251 disclosed?

CVE-2021-20251 was first published in the National Vulnerability Database on March 6, 2023, with the most recent update on November 21, 2024. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.

Is CVE-2021-20251 actively exploited?

CVE-2021-20251 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 44.8% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.

What is the CVSS score of CVE-2021-20251?

CVE-2021-20251 has a CVSS v3 base score of 5.9 (NVD).

How do I remediate CVE-2021-20251?

Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2021-20251, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

Dependency Blast Radius

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CVE-2021-20251

Published

Last Modified

References (8)

Patch Availability(1)

Weakness Classification(1)

All Vendor Advisories

Data Freshness Timeline

Frequently asked(5)

Dependency Blast Radius

Is Your Infrastructure Affected by CVE-2021-20251?

Same vendor

Same CWE

CVE-2021-20251

📅 Published

🔄 Last Modified

🔗 References (8)

Patch Availability(1)

Weakness Classification(1)

All Vendor Advisories

Data Freshness Timeline

❓ Frequently asked(5)

Dependency Blast Radius

Is Your Infrastructure Affected by CVE-2021-20251?

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References (8)

Frequently asked(5)

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