CVE-2011-2705

CVE-2011-2705 is a medium-severity vulnerability in Ruby-lang Ruby with a CVSS 2.0 base score of 5.0. 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-20.

Key facts

• Severity: Medium (CVSS 2.0 base score 5.0)
• EPSS exploit prediction: 2% (78th percentile)
• Actively exploited: Not listed in CISA KEV
• Weakness: CWE-20
• Affected product: Ruby-lang Ruby
• Published: 2011-08-05
• Last modified: 2026-06-16

Description

The SecureRandom.random_bytes function in lib/securerandom.rb in Ruby before 1.8.7-p352 and 1.9.x before 1.9.2-p290 relies on PID values for initialization, which makes it easier for context-dependent attackers to predict the result string by leveraging knowledge of random strings obtained in an earlier process with the same PID.

Frequently asked questions

What is CVE-2011-2705?

The SecureRandom.random_bytes function in lib/securerandom.rb in Ruby before 1.8.7-p352 and 1.9.x before 1.9.2-p290 relies on PID values for initialization, which makes it easier for context-dependent attackers to predict the result string by leveraging knowledge of random strings obtained in an earlier process with the same PID.

How severe is CVE-2011-2705?

CVE-2011-2705 has a CVSS 2.0 base score of 5.0, rated medium severity.

Is CVE-2011-2705 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (78th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2011-2705?

CVE-2011-2705 primarily affects Ruby-lang Ruby. In total, 35 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2011-2705?

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

When was CVE-2011-2705 published?

CVE-2011-2705 was published on 2011-08-05 and last updated on 2026-06-16.

References

• http://lists.fedoraproject.org/pipermail/package-announce/2011-July/063062.html
• http://lists.fedoraproject.org/pipermail/package-announce/2011-July/063071.html
• http://redmine.ruby-lang.org/issues/4579
• http://svn.ruby-lang.org/cgi-bin/viewvc.cgi?view=revision&revision=32050
• http://svn.ruby-lang.org/repos/ruby/tags/v1_8_7_352/ChangeLog
• http://svn.ruby-lang.org/repos/ruby/tags/v1_9_2_290/ChangeLog
• http://www.openwall.com/lists/oss-security/2011/07/11/1
• http://www.openwall.com/lists/oss-security/2011/07/12/14
• http://www.openwall.com/lists/oss-security/2011/07/20/1
• http://www.openwall.com/lists/oss-security/2011/07/20/16
• http://www.redhat.com/support/errata/RHSA-2011-1581.html
• http://www.ruby-lang.org/en/news/2011/07/02/ruby-1-8-7-p352-released/
• http://www.ruby-lang.org/en/news/2011/07/15/ruby-1-9-2-p290-is-released/
• http://www.securityfocus.com/bid/49015
• https://bugzilla.redhat.com/show_bug.cgi?id=722415

Affected products (35)

• cpe:2.3:a:ruby-lang:ruby:*:*:*:*:*:*:*:*
• cpe:2.3:a:ruby-lang:ruby:1.8.7:p22:*:*:*:*:*:*
• 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:1.8.7-160:*:*:*:*:*:*:*
• cpe:2.3:a:ruby-lang:ruby:1.8.7-173:*:*:*:*:*:*:*
• cpe:2.3:a:ruby-lang:ruby:1.8.7-248:*:*:*:*:*:*:*
• cpe:2.3:a:ruby-lang:ruby:1.8.7-249:*:*:*:*:*:*:*
• cpe:2.3:a:ruby-lang:ruby:1.8.7-299:*:*:*:*:*:*:*
• cpe:2.3:a:ruby-lang:ruby:1.8.7-302:*:*:*:*:*:*:*
• cpe:2.3:a:ruby-lang:ruby:1.8.7-330:*:*:*:*:*:*:*
• cpe:2.3:a:ruby-lang:ruby:1.8.7-p21:*:*:*:*:*:*:*
• cpe:2.3:a:ruby-lang:ruby:1.9:*:*:*:*:*:*:*
• cpe:2.3:a:ruby-lang:ruby:1.9:r18423:*:*:*:*:*:*
• cpe:2.3:a:ruby-lang:ruby:1.9.0:*:*:*:*:*:*:*
• cpe:2.3:a:ruby-lang:ruby:1.9.0:r18423:*:*:*:*:*:*
• cpe:2.3:a:ruby-lang:ruby:1.9.0-0:*:*:*:*:*:*:*
• cpe:2.3:a:ruby-lang:ruby:1.9.0-1:*:*:*:*:*:*:*
• cpe:2.3:a:ruby-lang:ruby:1.9.0-2:*:*:*:*:*:*:*
• cpe:2.3:a:ruby-lang:ruby:1.9.0-20060415:*:*:*:*:*:*:*
• cpe:2.3:a:ruby-lang:ruby:1.9.0-20070709:*:*:*:*:*:*:*
• cpe:2.3:a:ruby-lang:ruby:1.9.1:*:*:*:*:*:*:*
• cpe:2.3:a:ruby-lang:ruby:1.9.1:-p0:*:*:*:*:*:*
• cpe:2.3:a:ruby-lang:ruby:1.9.1:-p129:*:*:*:*:*:*
• cpe:2.3:a:ruby-lang:ruby:1.9.1:-p243:*:*:*:*:*:*
• cpe:2.3:a:ruby-lang:ruby:1.9.1:-p376:*:*:*:*:*:*
• cpe:2.3:a:ruby-lang:ruby:1.9.1:-p429:*:*:*:*:*:*
• cpe:2.3:a:ruby-lang:ruby:1.9.1:-preview_1:*:*:*:*:*:*
• cpe:2.3:a:ruby-lang:ruby:1.9.1:-preview_2:*:*:*:*:*:*
• cpe:2.3:a:ruby-lang:ruby:1.9.1:-rc1:*:*:*:*:*:*
• cpe:2.3:a:ruby-lang:ruby:1.9.1:-rc2:*:*:*:*:*:*
• cpe:2.3:a:ruby-lang:ruby:1.9.2:*:*:*:*:*:*:*
• cpe:2.3:a:ruby-lang:ruby:1.9.2:dev:*:*:*:*:*:*
• cpe:2.3:a:ruby-lang:ruby:1.9.2-p136:*:*:*:*:*:*:*
• cpe:2.3:a:ruby-lang:ruby:1.9.2-p180:*:*:*:*:*:*:*

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