CVE-2018-16395

Ruby Openssl Allows Incorrect Value Comparison

An issue was discovered in the OpenSSL library in Ruby 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.

CVE-2018-16395 has a CVSS score of 9.8 (Critical). The vector is network-reachable, no privileges required, and no user interaction. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. A fixed version is available (2.0.9, 2.1.2); upgrading removes the vulnerable code path.

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1. What is CVE-2018-16395? CVE-2018-16395 is a critical-severity security vulnerability in openssl (rubygems), affecting versions < 2.0.9. It is fixed in 2.0.9, 2.1.2.
2. How severe is CVE-2018-16395? CVE-2018-16395 has a CVSS score of 9.8 (Critical). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
3. Which versions of openssl are affected by CVE-2018-16395? openssl (rubygems) versions < 2.0.9 is affected.
4. Is there a fix for CVE-2018-16395? Yes. CVE-2018-16395 is fixed in 2.0.9, 2.1.2. Upgrade to this version or later.
5. Is CVE-2018-16395 exploitable, and should I be worried? Whether CVE-2018-16395 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
6. What actually determines whether CVE-2018-16395 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
7. How do I fix CVE-2018-16395?
   • Upgrade openssl to 2.0.9 or later
   • Upgrade openssl to 2.1.2 or later

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