CVE-2011-4838: JRuby before 1.6.5.1 computes hash values without restricting the ability to trigger hash collisions predic...

Security readout for executives and security teams

This is a denial-of-service issue in JRuby before 1.6.5.1. An attacker may be able to send specially crafted input that makes affected applications spend excessive CPU handling hash table collisions, slowing or stopping service. Exposure is most likely in applications running JRuby before 1.6.5.1 that accept untrusted input and store or parse it into hash tables. Public web endpoints are the main concern, but impact depends on application data flow. Treat this as a service-availability risk for legacy JRuby systems. It is not described as data theft or code execution, but internet-facing affected services could be disrupted if left unpatched. Mitigation focus: Upgrade JRuby to 1.6.5.1 or later where applicable.; Check JRuby and operating-system vendor advisories for package-specific fixes.; Prioritize externally reachable JRuby services that process untrusted request data..

Prepared

Jun 27, 2026, 17:28 UTC (UTC+00:00)

Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.