[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
Samba would allow unintended access to files over the network.
Software Description: – samba: SMB/CIFS file, print, and login server for Unix
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