Vulnerability Database

328,409

Total vulnerabilities in the database

CVE-2018-16395

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: Nov 16, 2018
  • Updated: Nov 9, 2025
  • CVE: CVE-2018-16395
  • Severity: High
  • Exploit:

CVSS v2:

  • Severity: High
  • Score: 7.5
  • AV:N/AC:L/Au:N/C:P/I:P/A:P

No CWE or OWASP classifications available.

Software From Fixed in
ruby-lang / ruby 2.6.0-preview1 2.6.0-preview1.x
ruby-lang / ruby 2.6.0-preview2 2.6.0-preview2.x
ruby-lang / ruby 2.3.0 2.3.7.x
ruby-lang / ruby 2.4.0 2.4.4.x
ruby-lang / ruby 2.5.0 2.5.1.x
ruby-lang / openssl - 2.1.2
canonical / ubuntu_linux 16.04 16.04.x
canonical / ubuntu_linux 14.04 14.04.x
canonical / ubuntu_linux 18.04 18.04.x
canonical / ubuntu_linux 18.10 18.10.x
debian / debian_linux 8.0 8.0.x
debian / debian_linux 9.0 9.0.x
redhat / enterprise_linux 7.4 7.4.x

Frequently Asked Questions

A security vulnerability is a weakness in software, hardware, or configuration that can be exploited to compromise confidentiality, integrity, or availability. Many vulnerabilities are tracked as CVEs (Common Vulnerabilities and Exposures), which provide a standardized identifier so teams can coordinate patching, mitigation, and risk assessment across tools and vendors.

CVSS (Common Vulnerability Scoring System) estimates technical severity, but it doesn't automatically equal business risk. Prioritize using context like internet exposure, affected asset criticality, known exploitation (proof-of-concept or in-the-wild), and whether compensating controls exist. A "Medium" CVSS on an exposed, production system can be more urgent than a "Critical" on an isolated, non-production host.

A vulnerability is the underlying weakness. An exploit is the method or code used to take advantage of it. A zero-day is a vulnerability that is unknown to the vendor or has no publicly available fix when attackers begin using it. In practice, risk increases sharply when exploitation becomes reliable or widespread.

Recurring findings usually come from incomplete Asset Discovery, inconsistent patch management, inherited images, and configuration drift. In modern environments, you also need to watch the software supply chain: dependencies, containers, build pipelines, and third-party services can reintroduce the same weakness even after you patch a single host. Unknown or unmanaged assets (often called Shadow IT) are a common reason the same issues resurface.

Use a simple, repeatable triage model: focus first on externally exposed assets, high-value systems (identity, VPN, email, production), vulnerabilities with known exploits, and issues that enable remote code execution or privilege escalation. Then enforce patch SLAs and track progress using consistent metrics so remediation is steady, not reactive.

SynScan combines attack surface monitoring and continuous security auditing to keep your inventory current, flag high-impact vulnerabilities early, and help you turn raw findings into a practical remediation plan.