CVE-2021-20254

Publication date 29 April 2021

Last updated 24 July 2024

Ubuntu priority

Cvss 3 Severity Score

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.

Read the notes from the security team

Status

Show unmaintained releases

Package	Ubuntu Release	Status
samba	21.04 hirsute	Fixed 2:4.13.3+dfsg-1ubuntu2.1
	20.10 groovy	Fixed 2:4.12.5+dfsg-3ubuntu4.3
	20.04 LTS focal	Fixed 2:4.11.6+dfsg-0ubuntu1.8
	18.04 LTS bionic	Fixed 2:4.7.6+dfsg~ubuntu-0ubuntu2.23
	16.04 LTS xenial	Fixed 2:4.3.11+dfsg-0ubuntu0.16.04.34
	14.04 LTS trusty	Fixed 2:4.3.11+dfsg-0ubuntu0.14.04.20+esm11 Ubuntu Pro

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Notes

mdeslaur

3.6 and higher

Severity score breakdown

Parameter	Value
Base score	6.8 · Medium
Attack vector	Network
Attack complexity	High
Privileges required	Low
User interaction	None
Scope	Unchanged
Confidentiality	High
Integrity impact	High
Availability impact	None
Vector	CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:N