CVE-2011-4838

MEDIUMCVSS v2 · 5.05.0—
EchelonGraph scoreLOW confidence

This CVE was only ever scored under CVSS v2.0. NVD CVSS v2.0 base 5.0 — v2 rates that MEDIUM (v2 bands: LOW 0.0–3.9 / MEDIUM 4.0–6.9 / HIGH 7.0–10.0; v2 has no CRITICAL band). Vector AV:N/AC:L/Au:N/C:N/I:N/A:P. CVSS v2 is an older, coarser metric than v3.1/v4.0 (no Scope, no User Interaction, no Attack Requirements), so it is not directly comparable to a v3 or v4 score. NVD has never re-scored this record under v3. EPSS predicts 4.4% exploitation probability in the next 30 days, which is reflected in EG Risk but does not lift the v2 base. Confidence: LOW.

Sources: epss, nvd_v2
5.0EG
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 4%CVSS v2: 5.0Exploit: None knownExposed: 0

A fix is available — apply it.

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.

CVSS v2.0 (legacy)
5.0MEDIUMNVD never assigned a CVSS v3 rating to this CVE
EG Score
5.0(low)
EG Risk
29(Track)
EG Risk 29/100SSVC: Track

EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).

How it’s computed
Severity50% × 45%
Exploitation4% × 40%
Automatability30% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
4%
EPSS %ILE
90%
KEV
Not listed

Published

December 30, 2011

Last Modified

April 29, 2026

References (20)

Patch Availability(1)

Vendor / EcosystemFixed in / PatchReleasedSource
redhatpatch2012-07-31redhat

Patches are aggregated from vendor advisories (Red Hat, Microsoft, Cisco, GitHub) and package ecosystems (OSV, GHSA). Multiple rows for the same upstream release have been deduplicated.

Affected Packages

(4 across 4 ecosystems)
Debian:12(1)
PackageVulnerable rangeFixed inDependents
jruby—1.5.6-4—
Debian:13(1)
PackageVulnerable rangeFixed inDependents
jruby—1.5.6-4—
Debian:14(1)
PackageVulnerable rangeFixed inDependents
jruby—1.5.6-4—
Debian:6.0(1)
PackageVulnerable rangeFixed inDependents
jruby1.3.1-2 ... 1.5.1-1 (6 versions)1.5.1-1+deb6u1—

Weakness Classification(1)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

All Vendor Advisories

(1)

Every vendor that published an advisory referencing this CVE — pulled from our cve_vendor_advisories aggregation. Click any row for the vendor's original advisory page.

Data Freshness Timeline

(refreshed 4× in last 7d / 16× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

Showing the most recent 100 of 127 total refreshes for this CVE.

  1. 2026-08-24 08:27 UTCOSV refresh
  2. 2026-08-23 00:12 UTCEPSS rescore
  3. 2026-08-21 23:43 UTCEPSS rescore
  4. 2026-08-19 16:59 UTCEPSS rescore
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  10. 2026-08-08 04:49 UTCOSV refresh
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  17. 2026-07-26 13:44 UTCEG score recompute▲ 5.00
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  20. 2026-07-23 01:06 UTCEG score recompute
  21. 2026-07-23 00:09 UTCEG score recompute
  22. 2026-07-22 21:54 UTCOSV refresh
  23. 2026-07-22 21:48 UTCEG score recompute
  24. 2026-07-22 14:04 UTCEPSS rescore
  25. 2026-07-22 14:04 UTCEPSS rescore
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  1. 2026-07-21 15:21 UTCEPSS rescore
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  20. 2026-07-05 16:59 UTCOSV refresh
  21. 2026-07-05 02:26 UTCEPSS rescore
  22. 2026-07-04 06:27 UTCEPSS rescore
  23. 2026-07-02 14:01 UTCEPSS rescore
  24. 2026-07-01 15:02 UTCEPSS rescore
  25. 2026-06-30 23:19 UTCEPSS rescore
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  27. 2026-06-29 14:02 UTCEPSS rescore
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  49. 2026-06-17 04:14 UTCOSV refresh
  50. 2026-06-16 17:49 UTCEPSS rescore
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Frequently asked(4)

What is CVE-2011-4838?
CVE-2011-4838 is a medium vulnerability published on December 30, 2011. 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.
When was CVE-2011-4838 disclosed?
CVE-2011-4838 was first published in the National Vulnerability Database on December 30, 2011, with the most recent update on April 29, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2011-4838 actively exploited?
CVE-2011-4838 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 4% probability of exploitation in the next 30 days, which ranks it in the top 9.8% of all scored CVEs.
How do I remediate CVE-2011-4838?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2011-4838, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

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