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.

Published: 2011-08-05 Last update: 2026-06-16 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2011-2705 is rated Moderate Risk (47.2/100): CVSS Medium severity, with medium exploitation likelihood (EPSS 1.95%). Review affected assets and schedule remediation.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Exploit prediction scoring system (EPSS) score for CVE-2011-2705

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 2026-06-18 1.97% 1.95% -0.02%
2 2026-06-15 0.99% 1.97% +0.98%
3 2025-12-28 — 0.99% —

Full EPSS history (14 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2011-2705

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
5.0 2.0 MEDIUM
AV:N/AC:L/Au:N/C:P/I:N/A:N Click to expand
Access vector (AV:N)
Can be exploited remotely over network reachability.
Access complexity (AC:L)
Exploitation conditions are straightforward and predictable.
Authentication (AU:N)
No authentication is required.
Confidentiality impact (C:P)
Partial confidentiality impact.
Integrity impact (I:N)
No integrity impact.
Availability impact (A:N)
No availability impact.
 10.0 2.9 [email protected]

Weakness enumeration for CVE-2011-2705

OS Trackers for CVE-2011-2705

vendor priority summary link
redhat low — https://access.redhat.com/security/cve/CVE-2011-2705
ubuntu medium CVE-2011-2705 medium priority: Ubuntu including 3 source packages (ruby1.8, ruby1.9, ruby1.9.1), 30 status rows across 10 suites (hardy, lucid, maverick, natty, oneiric, precise, quantal, raring, saucy, upstream): not-affected 10, DNE 8, ignored 6, released 5, needs-triage 1. https://ubuntu.com/security/CVE-2011-2705

Affected software / configurations for CVE-2011-2705

Vendor Product Version Raw CPE
ruby-lang ruby <= 1.8.7-334 cpe:2.3:a:ruby-lang:ruby:*:*:*:*:*:*:*:*
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:p71:*:*:*:*:*:*
ruby-lang ruby 1.8.7 cpe:2.3:a:ruby-lang:ruby:1.8.7:p72:*:*:*:*:*:*
ruby-lang ruby 1.8.7-160 cpe:2.3:a:ruby-lang:ruby:1.8.7-160:*:*:*:*:*:*:*
ruby-lang ruby 1.8.7-173 cpe:2.3:a:ruby-lang:ruby:1.8.7-173:*:*:*:*:*:*:*
ruby-lang ruby 1.8.7-248 cpe:2.3:a:ruby-lang:ruby:1.8.7-248:*:*:*:*:*:*:*
ruby-lang ruby 1.8.7-249 cpe:2.3:a:ruby-lang:ruby:1.8.7-249:*:*:*:*:*:*:*
ruby-lang ruby 1.8.7-299 cpe:2.3:a:ruby-lang:ruby:1.8.7-299:*:*:*:*:*:*:*
ruby-lang ruby 1.8.7-302 cpe:2.3:a:ruby-lang:ruby:1.8.7-302:*:*:*:*:*:*:*
ruby-lang ruby 1.8.7-330 cpe:2.3:a:ruby-lang:ruby:1.8.7-330:*:*:*:*:*:*:*
ruby-lang ruby 1.8.7-p21 cpe:2.3:a:ruby-lang:ruby:1.8.7-p21:*:*:*:*:*:*:*
ruby-lang ruby 1.9 cpe:2.3:a:ruby-lang:ruby:1.9:*:*:*:*:*:*:*
ruby-lang ruby 1.9 cpe:2.3:a:ruby-lang:ruby:1.9:r18423:*:*:*:*:*:*
ruby-lang ruby 1.9.0 cpe:2.3:a:ruby-lang:ruby:1.9.0:*:*:*:*:*:*:*
ruby-lang ruby 1.9.0 cpe:2.3:a:ruby-lang:ruby:1.9.0:r18423:*:*:*:*:*:*
ruby-lang ruby 1.9.0-0 cpe:2.3:a:ruby-lang:ruby:1.9.0-0:*:*:*:*:*:*:*
ruby-lang ruby 1.9.0-1 cpe:2.3:a:ruby-lang:ruby:1.9.0-1:*:*:*:*:*:*:*
ruby-lang ruby 1.9.0-2 cpe:2.3:a:ruby-lang:ruby:1.9.0-2:*:*:*:*:*:*:*
ruby-lang ruby 1.9.0-20060415 cpe:2.3:a:ruby-lang:ruby:1.9.0-20060415:*:*:*:*:*:*:*
ruby-lang ruby 1.9.0-20070709 cpe:2.3:a:ruby-lang:ruby:1.9.0-20070709:*:*:*:*:*:*:*
ruby-lang ruby 1.9.1 cpe:2.3:a:ruby-lang:ruby:1.9.1:*:*:*:*:*:*:*
ruby-lang ruby 1.9.1 cpe:2.3:a:ruby-lang:ruby:1.9.1:-p0:*:*:*:*:*:*
ruby-lang ruby 1.9.1 cpe:2.3:a:ruby-lang:ruby:1.9.1:-p129:*:*:*:*:*:*
ruby-lang ruby 1.9.1 cpe:2.3:a:ruby-lang:ruby:1.9.1:-p243:*:*:*:*:*:*
ruby-lang ruby 1.9.1 cpe:2.3:a:ruby-lang:ruby:1.9.1:-p376:*:*:*:*:*:*
ruby-lang ruby 1.9.1 cpe:2.3:a:ruby-lang:ruby:1.9.1:-p429:*:*:*:*:*:*
ruby-lang ruby 1.9.1 cpe:2.3:a:ruby-lang:ruby:1.9.1:-preview_1:*:*:*:*:*:*
ruby-lang ruby 1.9.1 cpe:2.3:a:ruby-lang:ruby:1.9.1:-preview_2:*:*:*:*:*:*
ruby-lang ruby 1.9.1 cpe:2.3:a:ruby-lang:ruby:1.9.1:-rc1:*:*:*:*:*:*
ruby-lang ruby 1.9.1 cpe:2.3:a:ruby-lang:ruby:1.9.1:-rc2:*:*:*:*:*:*
ruby-lang ruby 1.9.2 cpe:2.3:a:ruby-lang:ruby:1.9.2:*:*:*:*:*:*:*
ruby-lang ruby 1.9.2 cpe:2.3:a:ruby-lang:ruby:1.9.2:dev:*:*:*:*:*:*
ruby-lang ruby 1.9.2-p136 cpe:2.3:a:ruby-lang:ruby:1.9.2-p136:*:*:*:*:*:*:*
ruby-lang ruby 1.9.2-p180 cpe:2.3:a:ruby-lang:ruby:1.9.2-p180:*:*:*:*:*:*:*

References for CVE-2011-2705

URL Tags
http://lists.fedoraproject.org/pipermail/package-announce/2011-July/063062.html Patch
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 Patch
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 Patch
http://www.openwall.com/lists/oss-security/2011/07/12/14 Patch
http://www.openwall.com/lists/oss-security/2011/07/20/1 Patch
http://www.openwall.com/lists/oss-security/2011/07/20/16 Patch
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/ Patch
http://www.ruby-lang.org/en/news/2011/07/15/ruby-1-9-2-p290-is-released/ Patch
http://www.securityfocus.com/bid/49015
https://bugzilla.redhat.com/show_bug.cgi?id=722415 Patch
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