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5 <title>Samba 4.13.16 - Release Notes</title>
8 <H2>Samba 4.13.16 Available for Download</H2>
10 <a href="https://download.samba.org/pub/samba/stable/samba-4.13.16.tar.gz">Samba 4.13.16 (gzipped)</a><br>
11 <a href="https://download.samba.org/pub/samba/stable/samba-4.13.16.tar.asc">Signature</a>
14 <a href="https://download.samba.org/pub/samba/patches/samba-4.13.15-4.13.16.diffs.gz">Patch (gzipped) against Samba 4.13.15</a><br>
15 <a href="https://download.samba.org/pub/samba/patches/samba-4.13.15-4.13.16.diffs.asc">Signature</a>
19 ===============================
20 Release Notes for Samba 4.13.16
22 ===============================
25 This is a security release in order to address the following defects:
27 o CVE-2021-43566: mkdir race condition allows share escape in Samba 4.x.
28 https://www.samba.org/samba/security/CVE-2021-43566.html
36 All versions of Samba prior to 4.13.16 are vulnerable to a malicious
37 client using an SMB1 or NFS symlink race to allow a directory to be
38 created in an area of the server file system not exported under the
39 share definition. Note that SMB1 has to be enabled, or the share
40 also available via NFS in order for this attack to succeed.
42 Clients that have write access to the exported part of the file system
43 under a share via SMB1 unix extensions or NFS can create symlinks that
44 can race the server by renaming an existing path and then replacing it
45 with a symlink. If the client wins the race it can cause the server to
46 create a directory under the new symlink target after the exported
47 share path check has been done. This new symlink target can point to
48 anywhere on the server file system. The authenticated user must have
49 permissions to create a directory under the target directory of the
52 This is a difficult race to win, but theoretically possible. Note that
53 the proof of concept code supplied wins the race only when the server
54 is slowed down and put under heavy load. Exploitation of this bug has
55 not been seen in the wild.
61 o Jeremy Allison <jra@samba.org>
62 * BUG 13979: CVE-2021-43566: mkdir race condition allows share escape in Samba 4.x