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Fencer Intel
medium 5.0

CVE-2011-2686 json

Ruby before 1.8.7-p352 does not reset the random seed upon forking, which makes it easier for context-dependent attackers to predict the va…

published 2011-08-05 15 y ago modified 2026-06-16 4 mo ago also EUVD-2011-2668

cvss
5.0
version 2.0, NVD
cisa kev
Not listed
not in CISA's catalog
epss
2.6%
EPSS 2.6% chance of exploitation in 30 days, percentile 85%
public exploits
0
none known

Summary

Ruby before 1.8.7-p352 does not reset the random seed upon forking, which makes it easier for context-dependent attackers to predict the values of random numbers by leveraging knowledge of the number sequence obtained in a different child process, a related issue to CVE-2003-0900. NOTE: this issue exists because of a regression during Ruby 1.8.6 development.

Patch / fix

  • ruby4.0 hummingbird 1 4.0.0-33.3.hum1
  • ruby4.0-libs hummingbird 1 4.0.0-33.3.hum1
  • ruby4.0-bundled-gems hummingbird 1 4.0.0-33.3.hum1
  • ruby4.0-default-gems hummingbird 1 4.0.0-33.3.hum1
  • ruby3.3 hummingbird 1 3.3.10-23.1.hum1
  • ruby3.3-libs hummingbird 1 3.3.10-23.1.hum1
  • ruby3.3-bundled-gems hummingbird 1 3.3.10-23.1.hum1
  • ruby3.3-default-gems hummingbird 1 3.3.10-23.1.hum1

red hat advisories RHSA-2026:8838RHSA-2026:7305RHSA-2026:7307

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2011-2686 updated cvss 2.1

ruby: Properly initialize the random number generator when forking new process

  • Red Hat Enterprise Linux 4 ruby Red Hat Enterprise Linux 5 ruby Red Hat Enterprise Linux 6 ruby, ruby-ri, ruby-irb, ruby-libs, ruby-rdoc, ruby-tcltk
    affected: no fix available
  • Red Hat Hardened Images ruby3.4 3.4.8-31.1.hum1, ruby4.0 4.0.0-33.3.hum1, ruby3.3 3.3.10-23.1.hum1, ruby3.4-libs 3.4.8-31.1.hum1, ruby4.0-libs 4.0.0-33.3.hum1, ruby3.3-libs 3.3.10-23.1.hum1, +6 more
    fixed: vendor fix RHSA-2026:7305
  • Red Hat Hardened Images rubygem3.3-rbs 3.4.0-23.1.hum1, rubygem3.3-rss 0.3.1-23.1.hum1, rubygem3.4-rbs 3.8.0-31.1.hum1, rubygem3.4-rss 0.3.1-31.1.hum1, rubygem4.0-rss 0.3.2-33.3.hum1, rubygem3.3-irb 1.13.1-23.1.hum1, +45 more
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

Exploit prediction

2.58% chance of exploitation in the next 30 days, higher than 85% of all scored CVEs (FIRST EPSS, 2026-11-09).

CVSS scores

assigned by version score vector
NVD 2.0 5.0 AV:N/AC:L/Au:N/C:P/I:N/A:N

Classification

Weakness

References

Sources

Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.