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Fencer Intel
medium 5.0

CVE-2011-4838 json

JRuby before 1.6.5.1 computes hash values without restricting the ability to trigger hash collisions predictably, which allows context-depe…

published 2011-12-30 14 y ago modified 2026-06-16 4 mo ago also EUVD-2011-4756

cvss
5.0
version 2.0, NVD
cisa kev
Not listed
not in CISA's catalog
epss
4.2%
EPSS 4.2% chance of exploitation in 30 days, percentile 91%
public exploits
0
none known

Summary

JRuby before 1.6.5.1 computes hash values without restricting the ability to trigger hash collisions predictably, which allows context-dependent attackers to cause a denial of service (CPU consumption) via crafted input to an application that maintains a hash table.

Patch / fix

  • jruby jruby 1.6.5.1
  • jruby Debian 14, Debian 13, Debian 12 1.5.6-4

debian advisories DEBIAN-CVE-2011-4838

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-2011-4838 updated cvss 5.0

jruby: hash table collisions DoS (oCERT-2011-003)

  • Red Hat JBoss SOA Platform 5 jruby jruby
    affected: no fix available
  • Red Hat JBoss SOA Platform 5.3
    fixed: vendor fix RHSA-2012:1125

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

4.20% chance of exploitation in the next 30 days, higher than 91% 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:N/I:N/A:P

Classification

Weakness
  • CWE-400 Uncontrolled Resource Consumption

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.