CVE-2018-1139: Canonical Ubuntu Linux

High severity, CVSS 8.1. EPSS: 3.1% chance of exploitation in the next 30 days.

A flaw was found in the way samba before 4.7.9 and 4.8.4 allowed the use of weak NTLMv1 authentication even when NTLMv1 was explicitly disabled. A man-in-the-middle attacker could use this flaw to read the credential and other details passed between the samba server and client.

Affected products

• Canonical Ubuntu Linux: version 14.04 only; version 16.04 only; version 18.04 only
• Red Hat Enterprise Linux Desktop: version 7.0 only
• Red Hat Enterprise Linux Server: version 7.0 only
• Red Hat Enterprise Linux Workstation: version 7.0 only
• Samba Samba: from 4.7.0, before 4.7.9 (fixed in 4.7.9); from 4.8.0, before 4.8.4 (fixed in 4.8.4)

Published 2018-08-22. Last modified 2026-06-17.