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.
Conclusion & alert: CVE-2013-4073 is rated Moderate Risk (56.8/100): CVSS Medium severity, with medium exploitation likelihood (EPSS 2.77%). Mandatory action: Review affected assets and schedule remediation.
Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.
EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).
| # | Date | Old EPSS score | New EPSS score | Delta (New - Old) |
|---|---|---|---|---|
| 1 | 2026-06-23 | 2.74% | 2.77% | +0.02% |
| 2 | 2026-06-15 | 2.83% | 2.74% | -0.09% |
| 3 | 2026-06-04 | — | 2.83% | — |
Full EPSS history (23 records total)
CVSS metrics for this CVE.
| Base score | Version | Severity | Vector | Exploitability | Impact | Score source |
|---|---|---|---|---|---|---|
| 6.8 | 2.0 | MEDIUM |
|
8.6 | 6.4 | [email protected] |
| vendor | priority | summary | link |
|---|---|---|---|
debian
|
unimportant | CVE-2013-4073 unimportant priority: Debian including 1 source packages (puppet), 1 status rows across 1 suites (bullseye): resolved 1. | https://security-tracker.debian.org/tracker/CVE-2013-4073 |
redhat
|
medium | — | https://access.redhat.com/security/cve/CVE-2013-4073 |
ubuntu
|
medium | CVE-2013-4073 medium priority: Ubuntu including 2 source packages (ruby1.8, ruby1.9.1), 10 status rows across 5 suites (lucid, precise, quantal, raring, upstream): released 8, ignored 2. | https://ubuntu.com/security/CVE-2013-4073 |
| Vendor | Product | Version | Raw CPE |
|---|---|---|---|
| ruby-lang | ruby | 1.8.6-26 | cpe:2.3:a:ruby-lang:ruby:1.8.6-26:*:*:*:*:*:*:* |
| ruby-lang | ruby | 1.8.7 | cpe:2.3:a:ruby-lang:ruby:1.8.7:*:*:*:*:*:*:* |
| ruby-lang | ruby | 1.8.7 | cpe:2.3:a:ruby-lang:ruby:1.8.7:p160:*:*:*:*:*:* |
| ruby-lang | ruby | 1.8.7 | cpe:2.3:a:ruby-lang:ruby:1.8.7:p17:*:*:*:*:*:* |
| ruby-lang | ruby | 1.8.7 | cpe:2.3:a:ruby-lang:ruby:1.8.7:p173:*:*:*:*:*:* |
| ruby-lang | ruby | 1.8.7 | cpe:2.3:a:ruby-lang:ruby:1.8.7:p174:*:*:*:*:*:* |
| ruby-lang | ruby | 1.8.7 | cpe:2.3:a:ruby-lang:ruby:1.8.7:p22:*:*:*:*:*:* |
| ruby-lang | ruby | 1.8.7 | cpe:2.3:a:ruby-lang:ruby:1.8.7:p248:*:*:*:*:*:* |
| ruby-lang | ruby | 1.8.7 | cpe:2.3:a:ruby-lang:ruby:1.8.7:p249:*:*:*:*:*:* |
| ruby-lang | ruby | 1.8.7 | cpe:2.3:a:ruby-lang:ruby:1.8.7:p299:*:*:*:*:*:* |
| ruby-lang | ruby | 1.8.7 | cpe:2.3:a:ruby-lang:ruby:1.8.7:p301:*:*:*:*:*:* |
| ruby-lang | ruby | 1.8.7 | cpe:2.3:a:ruby-lang:ruby:1.8.7:p302:*:*:*:*:*:* |
| ruby-lang | ruby | 1.8.7 | cpe:2.3:a:ruby-lang:ruby:1.8.7:p330:*:*:*:*:*:* |
| ruby-lang | ruby | 1.8.7 | cpe:2.3:a:ruby-lang:ruby:1.8.7:p334:*:*:*:*:*:* |
| ruby-lang | ruby | 1.8.7 | cpe:2.3:a:ruby-lang:ruby:1.8.7:p352:*:*:*:*:*:* |
| ruby-lang | ruby | 1.8.7 | cpe:2.3:a:ruby-lang:ruby:1.8.7:p357:*:*:*:*:*:* |
| ruby-lang | ruby | 1.8.7 | cpe:2.3:a:ruby-lang:ruby:1.8.7:p358:*:*:*:*:*:* |
| ruby-lang | ruby | 1.8.7 | cpe:2.3:a:ruby-lang:ruby:1.8.7:p370:*:*:*:*:*:* |
| ruby-lang | ruby | 1.8.7 | cpe:2.3:a:ruby-lang:ruby:1.8.7:p371:*:*:*:*:*:* |
| ruby-lang | ruby | 1.8.7 | cpe:2.3:a:ruby-lang:ruby:1.8.7:p373:*:*:*:*:*:* |
| ruby-lang | ruby | 1.8.7 | cpe:2.3:a:ruby-lang:ruby:1.8.7:p71:*:*:*:*:*:* |
| ruby-lang | ruby | 1.8.7 | cpe:2.3:a:ruby-lang:ruby:1.8.7:p72:*:*:*:*:*:* |
| ruby-lang | ruby | 1.8.7 | cpe:2.3:a:ruby-lang:ruby:1.8.7:preview1:*:*:*:*:*:* |
| ruby-lang | ruby | 1.8.7 | cpe:2.3:a:ruby-lang:ruby:1.8.7:preview2:*:*:*:*:*:* |
| ruby-lang | ruby | 1.8.7 | cpe:2.3:a:ruby-lang:ruby:1.8.7:preview3:*:*:*:*:*:* |
| ruby-lang | ruby | 1.8.7 | cpe:2.3:a:ruby-lang:ruby:1.8.7:preview4:*:*:*:*:*:* |
| ruby-lang | ruby | 1.9.3 | cpe:2.3:a:ruby-lang:ruby:1.9.3:*:*:*:*:*:*:* |
| ruby-lang | ruby | 1.9.3 | cpe:2.3:a:ruby-lang:ruby:1.9.3:p0:*:*:*:*:*:* |
| ruby-lang | ruby | 1.9.3 | cpe:2.3:a:ruby-lang:ruby:1.9.3:p125:*:*:*:*:*:* |
| ruby-lang | ruby | 1.9.3 | cpe:2.3:a:ruby-lang:ruby:1.9.3:p194:*:*:*:*:*:* |
| ruby-lang | ruby | 1.9.3 | cpe:2.3:a:ruby-lang:ruby:1.9.3:p286:*:*:*:*:*:* |
| ruby-lang | ruby | 1.9.3 | cpe:2.3:a:ruby-lang:ruby:1.9.3:p383:*:*:*:*:*:* |
| ruby-lang | ruby | 1.9.3 | cpe:2.3:a:ruby-lang:ruby:1.9.3:p385:*:*:*:*:*:* |
| ruby-lang | ruby | 1.9.3 | cpe:2.3:a:ruby-lang:ruby:1.9.3:p392:*:*:*:*:*:* |
| ruby-lang | ruby | 1.9.3 | cpe:2.3:a:ruby-lang:ruby:1.9.3:p426:*:*:*:*:*:* |
| ruby-lang | ruby | 1.9.3 | cpe:2.3:a:ruby-lang:ruby:1.9.3:p429:*:*:*:*:*:* |
| ruby-lang | ruby | 2.0.0 | cpe:2.3:a:ruby-lang:ruby:2.0.0:p0:*:*:*:*:*:* |
| ruby-lang | ruby | 2.0.0 | cpe:2.3:a:ruby-lang:ruby:2.0.0:p195:*:*:*:*:*:* |
| ruby-lang | ruby | 2.0.0 | cpe:2.3:a:ruby-lang:ruby:2.0.0:preview1:*:*:*:*:*:* |
| ruby-lang | ruby | 2.0.0 | cpe:2.3:a:ruby-lang:ruby:2.0.0:preview2:*:*:*:*:*:* |
| ruby-lang | ruby | 2.0.0 | cpe:2.3:a:ruby-lang:ruby:2.0.0:rc1:*:*:*:*:*:* |
| ruby-lang | ruby | 2.0.0 | cpe:2.3:a:ruby-lang:ruby:2.0.0:rc2:*:*:*:*:*:* |