CVE-2021-20208

Publication date 19 April 2021

Last updated 7 August 2025

Ubuntu priority

Cvss 3 Severity Score

A flaw was found in cifs-utils in versions before 6.13. A user when mounting a krb5 CIFS file system from within a container can use Kerberos credentials of the host. 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
cifs-utils	25.04 plucky	Not affected
	24.10 oracular	Not affected
	24.04 LTS noble	Not affected
	23.10 mantic	Not affected
	23.04 lunar	Not affected
	22.10 kinetic	Not affected
	22.04 LTS jammy	Not affected
	21.10 impish	Not affected
	21.04 hirsute	Ignored end of life
	20.10 groovy	Ignored end of life
	20.04 LTS focal	Fixed 2:6.9-1ubuntu0.2
	18.04 LTS bionic	Fixed 2:6.8-1ubuntu1.2
	16.04 LTS xenial	Fixed 2:6.4-1ubuntu1.1+esm1
	14.04 LTS trusty	Fixed 2:6.0-1ubuntu2+esm1

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Notes

mdeslaur

per Red Hat bug, 6.13 was missing two important fixes, and 6.14 is required. per Debian, causes a regression, see: https://bugs.debian.org/989080 https://www.spinics.net/lists/linux-cifs/msg21976.html

Patch details

For informational purposes only. We recommend not to cherry-pick updates. How can I get the fixes?

Package	Patch details
cifs-utils	Upstream: https://git.samba.org/cifs-utils.git/?p=cifs-utils.git;a=commit;h=e461afd8cfa6d0781ae0c5c10e89b6ef1ca6da32 Upstream: https://git.samba.org/cifs-utils.git/?p=cifs-utils.git;a=commit;h=7f9711dd902a239c499682015d708f73ec884af2

Severity score breakdown

Parameter	Value
Base score	6.1 · Medium
Attack vector	Local
Attack complexity	High
Privileges required	Low
User interaction	Required
Scope	Changed
Confidentiality	Low
Integrity impact	High
Availability impact	None
Vector	CVSS:3.1/AV:L/AC:H/PR:L/UI:R/S:C/C:L/I:H/A:N