[USN-4930-1] Samba vulnerability

========================================================================== Ubuntu Security Notice USN-4930-1 April 29, 2021
samba vulnerability ==========================================================================
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: ubuntu.com/security/notices/USN-4930-1 CVE-2021-20254
Package Information: launchpad.net/ubuntu/+source/samba/2:4.13.3+dfsg-1ubuntu2.1 launchpad.net/ubuntu/+source/samba/2:4.12.5+dfsg-3ubuntu4.3 launchpad.net/ubuntu/+source/samba/2:4.11.6+dfsg-0ubuntu1.8 launchpad.net/ubuntu/+source/samba/2:4.7.6+dfsg~ubuntu-0ubuntu2.23 launchpad.net/ubuntu/+source/samba/2:4.3.11+dfsg-0ubuntu0.16.04.34