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.
Advisories
Source ID Title
Debian DLA Debian DLA DLA-2668-1 samba security update
EUVD EUVD EUVD-2021-7692 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.
Ubuntu USN Ubuntu USN USN-4930-1 Samba vulnerability
Ubuntu USN Ubuntu USN USN-4931-1 Samba vulnerabilities
Fixes

Solution

No solution given by the vendor.


Workaround

No workaround given by the vendor.

History

Sat, 12 Jul 2025 13:45:00 +0000

Type Values Removed Values Added
Metrics epss

{'score': 0.00314}

epss

{'score': 0.00341}


cve-icon MITRE

Status: PUBLISHED

Assigner: redhat

Published:

Updated: 2024-08-03T17:37:23.017Z

Reserved: 2020-12-17T00:00:00

Link: CVE-2021-20254

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Modified

Published: 2021-05-05T14:15:07.883

Modified: 2024-11-21T05:46:13.203

Link: CVE-2021-20254

cve-icon Redhat

Severity : Moderate

Publid Date: 2021-04-29T00:00:00Z

Links: CVE-2021-20254 - Bugzilla

cve-icon OpenCVE Enrichment

No data.