CVE-2016-2124
samba: SMB1 client connections can be downgraded to plaintext authentication
Severity
ModerateRed Hat Product Security
CVSS 3.1
Review impact separately from score.
Published · November 9, 2021
Updated · November 22, 2025
Description
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.
CVSS score applicability
The CVSS score(s) listed for this vulnerability do not reflect the associated product's status, and are included for informational purposes to better understand the severity of this vulnerability.
Mitigation
Ensure the following [global] smb.conf parameters are set to their default values as shown below:
client lanman auth = no
client NTLMv2 auth = yes
client plaintext auth = no
client min protocol = SMB2_02
Or use the '-k' command line option only without the -U option, which will make use of an existing krb5 ccache.
CVSS / CWE
CVSS 3.1 · 6.8CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:N
CWE-287 · Improper Authentication