After upgrade to RHEL 7.6 CIFS shares won't mount due to an auto-negotiation security settings mismatch error if the SMB server selects an SMBv3 dialect that isn't SMB3.02

Solution Verified - Updated -


  • Cannot mount cifs share when vers=default is used or version is not specified.
mount error(5): Input/output error
Refer to the mount.cifs(8) manual page (e.g. man mount.cifs)


  • Red Hat Enterprise Linux 7.6
    • seen on kernel-3.10.0-957.el7

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