Descriptionlibcli/smb/smbXcli_base.c in Samba 4.x before 4.2.14, 4.3.x before 4.3.11, and 4.4.x before 4.4.5 allows man-in-the-middle attackers to bypass a client-signing protection mechanism, and consequently spoof SMB2 and SMB3 servers, via the (1) SMB2_SESSION_FLAG_IS_GUEST or (2) SMB2_SESSION_FLAG_IS_NULL flag.
SourceCVE (at NVD; CERT, LWN, oss-sec, fulldisc, bugtraq, EDB, Metasploit, Red Hat, Ubuntu, Gentoo, SUSE bugzilla/CVE, Mageia, GitHub code/issues, web search, more)
NVD severitymedium (attack range: remote)
Debian Bugs830195

Vulnerable and fixed packages

The table below lists information on source packages.

Source PackageReleaseVersionStatus
samba (PTS)wheezy2:3.6.6-6+deb7u7fixed
wheezy (security)2:3.6.6-6+deb7u15fixed
jessie (security), jessie2:4.2.14+dfsg-0+deb8u9fixed
stretch (security), stretch2:4.5.12+dfsg-2+deb9u1fixed
buster, sid2:4.7.4+dfsg-1fixed

The information below is based on the following data on fixed versions.

PackageTypeReleaseFixed VersionUrgencyOriginDebian Bugs
sambasourcewheezy(not affected)


[wheezy] - samba <not-affected> (Affects Samba 4.0.0 to 4.4.0)
Affects Samba 4.0.0 to 4.4.4

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