{"id":"CVE-2018-16395","url":"https://www.cyber-defence.io/tools/cve/CVE-2018-16395","generatedAt":"2026-11-05T03:29:21.382Z","title":"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.","description":"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.","published":"2018-11-16T18:29:01.000Z","lastModified":"2026-06-17T01:44:13.000Z","status":"Modified","sourceIdentifier":"cve@mitre.org","cvss":{"version":"3.0","score":9.8,"severity":"CRITICAL","vector":"CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H"},"cwe":[],"affected":["ruby-lang/openssl","ruby-lang/ruby","canonical/ubuntu linux","debian/debian linux","redhat/enterprise linux"],"epss":{"score":0.10715,"percentile":0.95825,"date":"2026-11-03","history":[]},"kev":{"listed":false},"exploits":{"count":0,"verified":false,"firstPublished":null,"source":"Exploit-DB (https://gitlab.com/exploit-database/exploitdb)","entries":[]},"verdict":{"level":"urgent","text":"EPSS puts the probability of exploitation in the next 30 days at 10.7%, higher than 96% of all known CVEs. Patch or mitigate before the next change window."},"changes":[{"kind":"epss","label":"EPSS jump","at":"2026-09-22T00:00:00.000Z","detail":{"to":0.10715,"from":0.09882,"percentile":0.95615},"summary":"EPSS moved from 9.9% to 10.7% probability of exploitation in the next thirty days."}],"references":[{"url":"http://lists.opensuse.org/opensuse-security-announce/2019-07/msg00036.html","tags":["Mailing List","Third Party Advisory"],"source":"cve@mitre.org"},{"url":"http://www.securitytracker.com/id/1042105","tags":["Third Party Advisory","VDB Entry"],"source":"cve@mitre.org"},{"url":"https://access.redhat.com/errata/RHSA-2018:3729","tags":["Third Party Advisory"],"source":"cve@mitre.org"},{"url":"https://access.redhat.com/errata/RHSA-2018:3730","tags":["Third Party Advisory"],"source":"cve@mitre.org"},{"url":"https://access.redhat.com/errata/RHSA-2018:3731","tags":["Third Party Advisory"],"source":"cve@mitre.org"},{"url":"https://access.redhat.com/errata/RHSA-2018:3738","tags":["Third Party Advisory"],"source":"cve@mitre.org"},{"url":"https://access.redhat.com/errata/RHSA-2019:1948","tags":["Third Party Advisory"],"source":"cve@mitre.org"},{"url":"https://access.redhat.com/errata/RHSA-2019:2565","source":"cve@mitre.org"},{"url":"https://hackerone.com/reports/387250","tags":["Patch","Third Party Advisory"],"source":"cve@mitre.org"},{"url":"https://lists.debian.org/debian-lts-announce/2018/10/msg00020.html","tags":["Third Party Advisory"],"source":"cve@mitre.org"},{"url":"https://security.netapp.com/advisory/ntap-20190221-0002/","tags":["Third Party Advisory"],"source":"cve@mitre.org"},{"url":"https://usn.ubuntu.com/3808-1/","tags":["Third Party Advisory"],"source":"cve@mitre.org"},{"url":"https://www.debian.org/security/2018/dsa-4332","tags":["Third Party Advisory"],"source":"cve@mitre.org"},{"url":"https://www.oracle.com/security-alerts/cpujan2020.html","source":"cve@mitre.org"},{"url":"https://www.ruby-lang.org/en/news/2018/10/17/openssl-x509-name-equality-check-does-not-work-correctly-cve-2018-16395/","tags":["Mitigation","Vendor Advisory"],"source":"cve@mitre.org"},{"url":"https://www.ruby-lang.org/en/news/2018/10/17/ruby-2-3-8-released/","tags":["Release Notes","Vendor Advisory"],"source":"cve@mitre.org"},{"url":"https://www.ruby-lang.org/en/news/2018/10/17/ruby-2-4-5-released/","tags":["Release Notes","Vendor Advisory"],"source":"cve@mitre.org"},{"url":"https://www.ruby-lang.org/en/news/2018/10/17/ruby-2-5-2-released/","tags":["Release Notes","Vendor Advisory"],"source":"cve@mitre.org"},{"url":"https://www.ruby-lang.org/en/news/2018/11/06/ruby-2-6-0-preview3-released/","tags":["Release Notes","Vendor Advisory"],"source":"cve@mitre.org"},{"url":"http://lists.opensuse.org/opensuse-security-announce/2019-07/msg00036.html","tags":["Mailing List","Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"http://www.securitytracker.com/id/1042105","tags":["Third Party Advisory","VDB Entry"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://access.redhat.com/errata/RHSA-2018:3729","tags":["Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://access.redhat.com/errata/RHSA-2018:3730","tags":["Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://access.redhat.com/errata/RHSA-2018:3731","tags":["Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://access.redhat.com/errata/RHSA-2018:3738","tags":["Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://access.redhat.com/errata/RHSA-2019:1948","tags":["Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://access.redhat.com/errata/RHSA-2019:2565","source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://hackerone.com/reports/387250","tags":["Patch","Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://lists.debian.org/debian-lts-announce/2018/10/msg00020.html","tags":["Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://security.netapp.com/advisory/ntap-20190221-0002/","tags":["Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://usn.ubuntu.com/3808-1/","tags":["Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://www.debian.org/security/2018/dsa-4332","tags":["Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://www.oracle.com/security-alerts/cpujan2020.html","source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://www.ruby-lang.org/en/news/2018/10/17/openssl-x509-name-equality-check-does-not-work-correctly-cve-2018-16395/","tags":["Mitigation","Vendor Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://www.ruby-lang.org/en/news/2018/10/17/ruby-2-3-8-released/","tags":["Release Notes","Vendor Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://www.ruby-lang.org/en/news/2018/10/17/ruby-2-4-5-released/","tags":["Release Notes","Vendor Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://www.ruby-lang.org/en/news/2018/10/17/ruby-2-5-2-released/","tags":["Release Notes","Vendor Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://www.ruby-lang.org/en/news/2018/11/06/ruby-2-6-0-preview3-released/","tags":["Release Notes","Vendor Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"}],"sources":{"nvd":"https://nvd.nist.gov/vuln/detail/CVE-2018-16395","epss":"https://www.first.org/epss/","kev":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog","exploitdb":"https://www.exploit-db.com/"},"licence":"CC BY 4.0 — link back to the CVE Explorer if you publish the results; upstream data remains subject to its own terms."}