A Samba security update has been released for Ubuntu Linux 16.04 LTS, 18.04 LTS, 20.04 LTS, 20.10, and 21.04.
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Ubuntu Security Notice USN-4930-1
April 29, 2021
samba vulnerability
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A security issue affects these releases of Ubuntu and its derivatives:
- Ubuntu 21.04
- Ubuntu 20.10
- Ubuntu 20.04 LTS
- Ubuntu 18.04 LTS
- Ubuntu 16.04 LTS
Summary:
Samba would allow unintended access to files over the network.
Software Description:
- samba: SMB/CIFS file, print, and login server for Unix
Details:
Peter Eriksson discovered that Samba incorrectly handled certain negative
idmap cache entries. This issue could result in certain users gaining
unauthorized access to files, contrary to expected behaviour.
Update instructions:
The problem can be corrected by updating your system to the following
package versions:
Ubuntu 21.04:
samba 2:4.13.3+dfsg-1ubuntu2.1
Ubuntu 20.10:
samba 2:4.12.5+dfsg-3ubuntu4.3
Ubuntu 20.04 LTS:
samba 2:4.11.6+dfsg-0ubuntu1.8
Ubuntu 18.04 LTS:
samba 2:4.7.6+dfsg~ubuntu-0ubuntu2.23
Ubuntu 16.04 LTS:
samba 2:4.3.11+dfsg-0ubuntu0.16.04.34
In general, a standard system update will make all the necessary changes.
References:
https://ubuntu.com/security/notices/USN-4930-1
CVE-2021-20254
Package Information:
https://launchpad.net/ubuntu/+source/samba/2:4.13.3+dfsg-1ubuntu2.1
https://launchpad.net/ubuntu/+source/samba/2:4.12.5+dfsg-3ubuntu4.3
https://launchpad.net/ubuntu/+source/samba/2:4.11.6+dfsg-0ubuntu1.8
https://launchpad.net/ubuntu/+source/samba/2:4.7.6+dfsg~ubuntu-0ubuntu2.23
https://launchpad.net/ubuntu/+source/samba/2:4.3.11+dfsg-0ubuntu0.16.04.34
