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AUSCERT External Security Bulletin Redistribution
ESB-2021.1481
USN-4930-1: Samba vulnerability
30 April 2021
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AusCERT Security Bulletin Summary
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Product: samba
Publisher: Ubuntu
Operating System: Ubuntu
Impact/Access: Unauthorised Access -- Existing Account
Reduced Security -- Existing Account
Resolution: Patch/Upgrade
CVE Names: CVE-2021-20254
Reference: ESB-2021.1478
Original Bulletin:
https://ubuntu.com/security/notices/USN-4930-1
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USN-4930-1: Samba vulnerability
29 April 2021
Samba would allow unintended access to files over the network.
Releases
o Ubuntu 21.04
o Ubuntu 20.10
o Ubuntu 20.04 LTS
o Ubuntu 18.04 LTS
o Ubuntu 16.04 LTS
Packages
o 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
o samba - 2:4.13.3+dfsg-1ubuntu2.1
Ubuntu 20.10
o samba - 2:4.12.5+dfsg-3ubuntu4.3
Ubuntu 20.04
o samba - 2:4.11.6+dfsg-0ubuntu1.8
Ubuntu 18.04
o samba - 2:4.7.6+dfsg~ubuntu-0ubuntu2.23
Ubuntu 16.04
o samba - 2:4.3.11+dfsg-0ubuntu0.16.04.34
In general, a standard system update will make all the necessary changes.
References
o CVE-2021-20254
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