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CVE-2018-16395

36
FAUCET Score

CVE-2018-16395 describes a critical vulnerability in the OpenSSL library used by Ruby versions before 2.3.8, 2.4.5, 2.5.2, and 2.6.0-preview3, affecting products from Canonical, Debian, Red Hat, and Ruby_lang. This flaw allows non-equal OpenSSL::X509::Name objects to be incorrectly identified as equal during comparison, potentially enabling the acceptance of illegitimate certificates for signing or encryption. With a CVSS score of 9.8 (CRITICAL), this vulnerability presents a high risk due to its network-based attack vector, low attack complexity, and severe impact on confidentiality, integrity, and availability. Despite its criticality, there is no evidence of active exploitation, public exploit code (Metasploit, Nuclei, ExploitDB), or significant community discussion or media coverage.

Impacted Technologies

VendorProductVersion(s)CPE
< 2.1.2CPE matchmatch criteria
cpe:2.3:a:ruby-lang:openssl:*:*:*:*:*:ruby:*:*
>= 2.3.0, <= 2.3.7CPE matchmatch criteria
cpe:2.3:a:ruby-lang:ruby:*:*:*:*:*:*:*:*
>= 2.4.0, <= 2.4.4CPE matchmatch criteria
cpe:2.3:a:ruby-lang:ruby:*:*:*:*:*:*:*:*
>= 2.5.0, <= 2.5.1CPE matchmatch criteria
cpe:2.3:a:ruby-lang:ruby:*:*:*:*:*:*:*:*
2.6.0CPE matchmatch criteria
cpe:2.3:a:ruby-lang:ruby:2.6.0:preview1:*:*:*:*:*:*

CVSS Data

CVSS version used by this source: 3.0

9.8CRITICAL

CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality Impact
HIGH
Integrity Impact
HIGH
Availability Impact
HIGH
Exploitability Score
3.9
Impact Score
5.9
CvssVersion
3.0

Exploit Intelligence

EPSS Score
10.71%
Probability of exploitation in next 30 days
EPSS Percentile
95.4%
Percentile rank of EPSS score among Peer Group
As of 2026-07-24
Model: v2026.06.15
This CVE's current EPSS score of 0.1071 is in the 91st percentile among its peer group of 36,821 CVEs.

Social Chatter

The average CVE in this peer group has 0.0 Twitter, 0.1 Reddit, 0.3 Bluesky, 0.3 Mastodon, and 2.4 GitHub mentions.

Media Mentions

No media coverage found for this CVE.

The average CVE in this peer group has 0.3 InfoSec Media, 0.0 Vendor Blog, and 0.0 Security Researcher mentions.

Remediation

Patch Available

Vendor Patches (27)

microsoftpatch availablevia msrc
Product: CBL Mariner 1.0 x64Fixed in: 1.1.1k-5
microsoftpatch availablevia msrc
Product: CBL Mariner 1.0 ARMFixed in: 1.1.1k-5
microsoftpatch availablevia msrc
Product: 16878-16820Fixed in: -
microsoftpatch availablevia msrc
Product: cm1 openssl 1.1.1k-5 on CBL Mariner 1.0Fixed in: -
redhatpatch availablevia redhat_api
Product: Red Hat Software Collections for Red Hat Enterprise Linux 6Fixed in: rh-ruby23-ruby-0:2.3.8-69.el6
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Software Collections for Red Hat Enterprise Linux 6Fixed in: rh-ruby24-ruby-0:2.4.5-91.el6
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Software Collections for Red Hat Enterprise Linux 7Fixed in: rh-ruby23-ruby-0:2.3.8-69.el7
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Software Collections for Red Hat Enterprise Linux 7Fixed in: rh-ruby24-ruby-0:2.4.5-91.el7
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Software Collections for Red Hat Enterprise Linux 7Fixed in: rh-ruby25-ruby-0:2.5.3-6.el7
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Software Collections for Red Hat Enterprise Linux 7.4 EUSFixed in: rh-ruby23-ruby-0:2.3.8-69.el7
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Software Collections for Red Hat Enterprise Linux 7.4 EUSFixed in: rh-ruby25-ruby-0:2.5.3-6.el7
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Software Collections for Red Hat Enterprise Linux 7.5 EUSFixed in: rh-ruby23-ruby-0:2.3.8-69.el7
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Software Collections for Red Hat Enterprise Linux 7.5 EUSFixed in: rh-ruby24-ruby-0:2.4.5-91.el7
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Software Collections for Red Hat Enterprise Linux 7.5 EUSFixed in: rh-ruby25-ruby-0:2.5.3-6.el7
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Software Collections for Red Hat Enterprise Linux 7.6 EUSFixed in: rh-ruby23-ruby-0:2.3.8-69.el7
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Software Collections for Red Hat Enterprise Linux 7.6 EUSFixed in: rh-ruby24-ruby-0:2.4.5-91.el7
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Software Collections for Red Hat Enterprise Linux 7.6 EUSFixed in: rh-ruby25-ruby-0:2.5.3-6.el7
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Software Collections for Red Hat Enterprise Linux 7.4 EUSFixed in: rh-ruby24-ruby-0:2.4.5-91.el7
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Enterprise Linux 7Fixed in: ruby-0:2.0.0.648-34.el7_6
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Enterprise Linux 7.4 Extended Update SupportFixed in: ruby-0:2.0.0.648-34.el7_4
View patch
redhatpatch availablevia redhat_api
Product: Red Hat Enterprise Linux 7.5 Extended Update SupportFixed in: ruby-0:2.0.0.648-34.el7_5
View patch
rubygemspatch availablevia ghsa
Product: opensslFixed in: 2.0.9
rubygemspatch availablevia ghsa
Product: opensslFixed in: 2.1.2
redhatend of lifevia redhat_api
Product: Red Hat Enterprise Linux 5Fixed in: ruby
redhatend of lifevia redhat_api
Product: Red Hat Enterprise Linux 6Fixed in: ruby
redhatend of lifevia redhat_api
Product: Red Hat Subscription Asset ManagerFixed in: ruby193
redhatend of lifevia redhat_api
Product: Red Hat Virtualization 4Fixed in: ruby

Vendor Advisories (4)

rubygemsGHSA-mmrq-6999-72v8critical

Ruby Openssl Allows Incorrect Value Comparison

May 13, 2022
microsoft2020-Sep/CVE-2018-16395

CVE-2018-16395

Sep 8, 2020
microsoft2018-Nov/CVE-2018-16395Critical

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.

Nov 13, 2018
redhatCVE-2018-16395Important

ruby: OpenSSL::X509:: Name equality check does not work correctly

Oct 17, 2018

References

lists.opensuse.org / opensuse-security-announce/2019-07/msg00036.html
Mailing ListThird Party Advisory
access.redhat.com / errata/RHSA-2018:3729
Third Party Advisory
access.redhat.com / errata/RHSA-2018:3730
Third Party Advisory
access.redhat.com / errata/RHSA-2018:3731
Third Party Advisory
access.redhat.com / errata/RHSA-2018:3738
Third Party Advisory
access.redhat.com / errata/RHSA-2019:1948
Third Party Advisory
access.redhat.com / errata/RHSA-2019:2565
hackerone.com / reports/387250
PatchThird Party Advisory
lists.debian.org / debian-lts-announce/2018/10/msg00020.html
Third Party Advisory
security.netapp.com / advisory/ntap-20190221-0002
Third Party Advisory
usn.ubuntu.com / 3808-1
Third Party Advisory
debian.org / security/2018/dsa-4332
Third Party Advisory
oracle.com / security-alerts/cpujan2020.html
ruby-lang.org / en/news/2018/10/17/openssl-x509-name-equality-check-does-not-work-correctly-cve-2018-16395
MitigationVendor Advisory
ruby-lang.org / en/news/2018/10/17/ruby-2-3-8-released
Release NotesVendor Advisory
ruby-lang.org / en/news/2018/10/17/ruby-2-4-5-released
Release NotesVendor Advisory
ruby-lang.org / en/news/2018/10/17/ruby-2-5-2-released
Release NotesVendor Advisory
ruby-lang.org / en/news/2018/11/06/ruby-2-6-0-preview3-released
Release NotesVendor Advisory
securitytracker.com / id/1042105
Third Party AdvisoryVDB Entry