CVE-2018-16395: Canonical Ubuntu Linux

Critical severity, CVSS 9.8. EPSS: 10.7% chance of exploitation in the next 30 days.

An issue was discovered in the OpenSSL library in Ruby before 2.3.8, 2.4.x before 2.4.5, 2.5.x before 2.5.2, and 2.6.x before 2.6.0-preview3. When two OpenSSL::X509::Name objects are compared using ==, depending on the ordering, non-equal objects may return true. When the first argument is one character longer than the second, or the second argument contains a character that is one less than a character in the same position of the first argument, the result of == will be true. This could be leveraged to create an illegitimate certificate that may be accepted as legitimate and then used in signing or encryption operations.

Affected products

• Canonical Ubuntu Linux: version 14.04 only; version 16.04 only; version 18.04 only; version 18.10 only
• Debian Debian Linux: version 8.0 only; version 9.0 only
• Red Hat Enterprise Linux: version 7.4 only
• Ruby-Lang OpenSSL: before 2.1.2 (fixed in 2.1.2)
• Ruby-Lang Ruby: from 2.3.0, up to and including 2.3.7; from 2.4.0, up to and including 2.4.4; from 2.5.0, up to and including 2.5.1; version 2.6.0 only

Published 2018-11-16. Last modified 2026-06-17.