CVE-2011-4838

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.

Published: 2011-12-30 Last update: 2026-04-29 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2011-4838 is rated Moderate Risk (46.8/100): CVSS Medium severity, with high exploitation likelihood (EPSS 7.27%, 91th percentile). EPSS ranks this CVE among the most likely to be exploited in the near term. High exploitation likelihood—assess exposure and prioritize 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-2011-4838

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 2025-03-30 13.31% 7.27% -6.03%
2 2025-03-29 7.27% 13.31% +6.03%
3 2025-03-17 — 7.27% —

Full EPSS history (5 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2011-4838

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:N/I:N/A:P 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:N)
No confidentiality impact.
Integrity impact (I:N)
No integrity impact.
Availability impact (A:P)
Partial availability impact.
 10.0 2.9 [email protected]

Weakness enumeration for CVE-2011-4838

OS Trackers for CVE-2011-4838

vendor priority summary link
debian low CVE-2011-4838 low priority: Debian including 1 source packages (jruby), 4 status rows across 4 suites (bookworm, forky, sid, trixie): resolved 4. https://security-tracker.debian.org/tracker/CVE-2011-4838
gentoo normal CVE-2011-4838: 1 GLSA(s) (201207-06), 1 atom(s) (dev-java/jruby); latest impact normal. https://bugs.gentoo.org/buglist.cgi?quicksearch=CVE-2011-4838
redhat medium — https://access.redhat.com/security/cve/CVE-2011-4838
ubuntu medium CVE-2011-4838 medium priority: Ubuntu including 1 source packages (jruby), 17 status rows across 17 suites (hardy, lucid, maverick, natty, oneiric, precise, quantal, raring, saucy, trusty, upstream, utopic, vivid, wily, xenial, yakkety, zesty): not-affected 10, ignored 5, DNE 1, released 1. https://ubuntu.com/security/CVE-2011-4838

Affected software / configurations for CVE-2011-4838

Vendor Product Version Raw CPE
jruby jruby < 1.6.5.1 cpe:2.3:a:jruby:jruby:*:*:*:*:*:*:*:*

References for CVE-2011-4838

cvelogic Threat Intelligence