CVE-2013-4073

CVE-2013-4073 is a medium-severity vulnerability in Ruby-lang Ruby with a CVSS 2.0 base score of 6.8. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-310.

Key facts

• Severity: Medium (CVSS 2.0 base score 6.8)
• EPSS exploit prediction: 3% (85th percentile)
• Actively exploited: Not listed in CISA KEV
• Weakness: CWE-310
• Affected product: Ruby-lang Ruby
• Published: 2013-08-18
• Last modified: 2026-06-16

Description

The OpenSSL::SSL.verify_certificate_identity function in lib/openssl/ssl.rb in Ruby 1.8 before 1.8.7-p374, 1.9 before 1.9.3-p448, and 2.0 before 2.0.0-p247 does not properly handle a '\0' character in a domain name in the Subject Alternative Name field of an X.509 certificate, which allows man-in-the-middle attackers to spoof arbitrary SSL servers via a crafted certificate issued by a legitimate Certification Authority, a related issue to CVE-2009-2408.

Frequently asked questions

What is CVE-2013-4073?

The OpenSSL::SSL.verify_certificate_identity function in lib/openssl/ssl.rb in Ruby 1.8 before 1.8.7-p374, 1.9 before 1.9.3-p448, and 2.0 before 2.0.0-p247 does not properly handle a '\0' character in a domain name in the Subject Alternative Name field of an X.509 certificate, which allows man-in-the-middle attackers to spoof arbitrary SSL servers via a crafted certificate issued by a legitimate Certification Authority, a related issue to CVE-2009-2408.

How severe is CVE-2013-4073?

CVE-2013-4073 has a CVSS 2.0 base score of 6.8, rated medium severity.

Is CVE-2013-4073 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 3% (85th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2013-4073?

CVE-2013-4073 primarily affects Ruby-lang Ruby. In total, 42 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2013-4073?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

When was CVE-2013-4073 published?

CVE-2013-4073 was published on 2013-08-18 and last updated on 2026-06-16.

References

• http://forums.interworx.com/threads/8000-InterWorx-Version-5-0-14-Released-on-Beta-Channel%21
• http://lists.apple.com/archives/security-announce/2013/Oct/msg00004.html
• http://lists.opensuse.org/opensuse-updates/2013-07/msg00042.html
• http://lists.opensuse.org/opensuse-updates/2013-07/msg00044.html
• http://rhn.redhat.com/errata/RHSA-2013-1090.html
• http://rhn.redhat.com/errata/RHSA-2013-1103.html
• http://rhn.redhat.com/errata/RHSA-2013-1137.html
• http://support.apple.com/kb/HT6150
• http://www.debian.org/security/2013/dsa-2738
• http://www.debian.org/security/2013/dsa-2809
• http://www.ruby-lang.org/en/news/2013/06/27/hostname-check-bypassing-vulnerability-in-openssl-client-cve-2013-4073/
• http://www.ubuntu.com/usn/USN-1902-1
• https://bugzilla.redhat.com/show_bug.cgi?id=979251
• https://puppet.com/security/cve/cve-2013-4073

Affected products (42)

• cpe:2.3:a:ruby-lang:ruby:1.8.6-26:*:*:*:*:*:*:*
• cpe:2.3:a:ruby-lang:ruby:1.8.7:*:*:*:*:*:*:*
• cpe:2.3:a:ruby-lang:ruby:1.8.7:p160:*:*:*:*:*:*
• cpe:2.3:a:ruby-lang:ruby:1.8.7:p17:*:*:*:*:*:*
• cpe:2.3:a:ruby-lang:ruby:1.8.7:p173:*:*:*:*:*:*
• cpe:2.3:a:ruby-lang:ruby:1.8.7:p174:*:*:*:*:*:*
• cpe:2.3:a:ruby-lang:ruby:1.8.7:p22:*:*:*:*:*:*
• cpe:2.3:a:ruby-lang:ruby:1.8.7:p248:*:*:*:*:*:*
• cpe:2.3:a:ruby-lang:ruby:1.8.7:p249:*:*:*:*:*:*
• cpe:2.3:a:ruby-lang:ruby:1.8.7:p299:*:*:*:*:*:*
• cpe:2.3:a:ruby-lang:ruby:1.8.7:p301:*:*:*:*:*:*
• cpe:2.3:a:ruby-lang:ruby:1.8.7:p302:*:*:*:*:*:*
• cpe:2.3:a:ruby-lang:ruby:1.8.7:p330:*:*:*:*:*:*
• cpe:2.3:a:ruby-lang:ruby:1.8.7:p334:*:*:*:*:*:*
• cpe:2.3:a:ruby-lang:ruby:1.8.7:p352:*:*:*:*:*:*
• cpe:2.3:a:ruby-lang:ruby:1.8.7:p357:*:*:*:*:*:*
• cpe:2.3:a:ruby-lang:ruby:1.8.7:p358:*:*:*:*:*:*
• cpe:2.3:a:ruby-lang:ruby:1.8.7:p370:*:*:*:*:*:*
• cpe:2.3:a:ruby-lang:ruby:1.8.7:p371:*:*:*:*:*:*
• cpe:2.3:a:ruby-lang:ruby:1.8.7:p373:*:*:*:*:*:*
• cpe:2.3:a:ruby-lang:ruby:1.8.7:p71:*:*:*:*:*:*
• cpe:2.3:a:ruby-lang:ruby:1.8.7:p72:*:*:*:*:*:*
• cpe:2.3:a:ruby-lang:ruby:1.8.7:preview1:*:*:*:*:*:*
• cpe:2.3:a:ruby-lang:ruby:1.8.7:preview2:*:*:*:*:*:*
• cpe:2.3:a:ruby-lang:ruby:1.8.7:preview3:*:*:*:*:*:*
• cpe:2.3:a:ruby-lang:ruby:1.8.7:preview4:*:*:*:*:*:*
• cpe:2.3:a:ruby-lang:ruby:1.9.3:*:*:*:*:*:*:*
• cpe:2.3:a:ruby-lang:ruby:1.9.3:p0:*:*:*:*:*:*
• cpe:2.3:a:ruby-lang:ruby:1.9.3:p125:*:*:*:*:*:*
• cpe:2.3:a:ruby-lang:ruby:1.9.3:p194:*:*:*:*:*:*
• cpe:2.3:a:ruby-lang:ruby:1.9.3:p286:*:*:*:*:*:*
• cpe:2.3:a:ruby-lang:ruby:1.9.3:p383:*:*:*:*:*:*
• cpe:2.3:a:ruby-lang:ruby:1.9.3:p385:*:*:*:*:*:*
• cpe:2.3:a:ruby-lang:ruby:1.9.3:p392:*:*:*:*:*:*
• cpe:2.3:a:ruby-lang:ruby:1.9.3:p426:*:*:*:*:*:*
• cpe:2.3:a:ruby-lang:ruby:1.9.3:p429:*:*:*:*:*:*
• cpe:2.3:a:ruby-lang:ruby:2.0.0:p0:*:*:*:*:*:*
• cpe:2.3:a:ruby-lang:ruby:2.0.0:p195:*:*:*:*:*:*
• cpe:2.3:a:ruby-lang:ruby:2.0.0:preview1:*:*:*:*:*:*
• cpe:2.3:a:ruby-lang:ruby:2.0.0:preview2:*:*:*:*:*:*

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