Samba 4.13.16 Available for Download

Samba 4.13.16 (gzipped)

Patch (gzipped) against Samba 4.13.15

                   Release Notes for Samba 4.13.16
                          January 10, 2022

This is a security release in order to address the following defects:

o CVE-2021-43566:  mkdir race condition allows share escape in Samba 4.x.


o  CVE-2021-43566:
   All versions of Samba prior to 4.13.16 are vulnerable to a malicious
   client using an SMB1 or NFS symlink race to allow a directory to be
   created in an area of the server file system not exported under the
   share definition. Note that SMB1 has to be enabled, or the share
   also available via NFS in order for this attack to succeed.

   Clients that have write access to the exported part of the file system
   under a share via SMB1 unix extensions or NFS can create symlinks that
   can race the server by renaming an existing path and then replacing it
   with a symlink. If the client wins the race it can cause the server to
   create a directory under the new symlink target after the exported
   share path check has been done. This new symlink target can point to
   anywhere on the server file system. The authenticated user must have
   permissions to create a directory under the target directory of the

   This is a difficult race to win, but theoretically possible. Note that
   the proof of concept code supplied wins the race only when the server
   is slowed down and put under heavy load. Exploitation of this bug has
   not been seen in the wild.

Changes since 4.13.15

o  Jeremy Allison <>
   * BUG 13979: CVE-2021-43566: mkdir race condition allows share escape in Samba 4.x