Several vulnerabilities were discovered in Samba, the SMB/CIFS file, print, and
login server for Unix.
A flaw was found in the way samba implemented SMB1 authentication. An
attacker could use this flaw to retrieve the plaintext password sent over
the wire even if Kerberos authentication was required.
A flaw was found in the samba client, all samba versions before samba
4.11.2, 4.10.10 and 4.9.15, where a malicious server can supply a pathname
to the client with separators. This could allow the client to access files
and folders outside of the SMB network pathnames. An attacker could use this
vulnerability to create files outside of the current working directory using
the privileges of the client user.
A flaw was found in Samba, all versions starting samba 4.5.0 before samba
4.9.15, samba 4.10.10, samba 4.11.2, in the way it handles a user password
change or a new password for a samba user. The Samba Active Directory Domain
Controller can be configured to use a custom script to check for password
complexity. This configuration can fail to verify password complexity when
non-ASCII characters are used in the password, which could lead to weak
passwords being set for samba users, making it vulnerable to dictionary
A flaw was found in samba 4.0.0 before samba 4.9.15 and samba 4.10.x before
4.10.10. An attacker can crash AD DC LDAP server via dirsync resulting in
denial of service. Privilege escalation is not possible with this issue.
There is an issue in all samba 4.11.x versions before 4.11.5, all samba
4.10.x versions before 4.10.12 and all samba 4.9.x versions before 4.9.18,
where the removal of the right to create or modify a subtree would not
automatically be taken away on all domain controllers.
All samba versions 4.9.x before 4.9.18, 4.10.x before 4.10.12 and 4.11.x
before 4.11.5 have an issue where if it is set with "log level = 3" (or
above) then the string obtained from the client, after a failed character
conversion, is printed. Such strings can be provided during the NTLMSSP
authentication exchange. In the Samba AD DC in particular, this may cause a
long-lived process(such as the RPC server) to terminate. (In the file server
case, the most likely target, smbd, operates as process-per-client and so a
crash there is harmless).
There is a use-after-free issue in all samba 4.9.x versions before 4.9.18,
all samba 4.10.x versions before 4.10.12 and all samba 4.11.x versions
before 4.11.5, essentially due to a call to realloc() while other local
variables still point at the original buffer.
For Debian 10 buster, these problems have been fixed in version
We recommend that you upgrade your samba packages.
Admins of AD DC setups are reminded and strongly encouraged to upgrade to
bullseye and then bookworm, as AD DC setups are unsupported in buster since DSA
5015-1, and in bullseye since DSA 5477-1.
For the detailed security status of samba please refer to
its security tracker page at:
Further information about Debian LTS security advisories, how to apply
these updates to your system and frequently asked questions can be
found at: https://wiki.debian.org/LTS