Denial of Service Vulnerability in JRuby - CVE-2011-4838
Summary
DEBIAN-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... Affects jruby versions < 1.5.6-4. Fixed in 1.5.6-4. How to fix ↓
Check if this vulnerability affects your application
Upload a manifest or SBOM and we'll show whether you're affected, plus every other risky package in the same scan.
No signup required · Results in about 60 seconds
Background
JRuby is an implementation of the Ruby programming language on the Java Virtual Machine (JVM). It allows Ruby applications to run on the JVM, providing access to Java libraries and performance optimizations. The package is widely used for web applications and other software that benefits from Ruby's syntax and features. However, prior to version 1.6.5.1, JRuby had a vulnerability that allowed attackers to exploit hash collisions, leading to potential denial of service.
Vulnerability Detail
The vulnerability identified as CVE-2011-4838 in JRuby arises from its method of computing hash values without adequate restrictions. This flaw enables attackers to craft specific inputs that can trigger predictable hash collisions. When such collisions occur, they can significantly increase CPU consumption, leading to a denial of service. This vulnerability is particularly concerning for applications that rely on hash tables for data storage and retrieval, as it can degrade performance and availability.
How To Fix
Minimum fixed version
1.5.6-4
This is the first release that contains the fix.
sudo apt-get install --only-upgrade jrubyTip — Not sure which version your app runs? Vulert can match this fix to it. Scan free →
Workaround
As a temporary workaround, developers can implement input validation to limit the types of data that can be processed by the application, thereby reducing the risk of triggering hash collisions. Additionally, consider using alternative data structures that are less susceptible to such attacks.
Conclusion
The CVE-2011-4838 vulnerability in JRuby poses a significant risk of denial of service due to predictable hash collisions. Users are strongly advised to upgrade to the patched version to ensure the security and stability of their applications. Temporary workarounds can help mitigate the risk until an upgrade is feasible.
See every vulnerability recorded for jruby →
FAQ
CVE-2011-4838 is a vulnerability in JRuby that allows attackers to exploit hash collisions, leading to denial of service through excessive CPU consumption.
You can check if your application is affected by using the Vulert playground at Vulert Scanner, which analyzes your manifest file for vulnerabilities.
JRuby versions prior to 1.6.5.1 are vulnerable to this issue. It is essential to upgrade to version 1.5.6-4 or later to mitigate the risk.
The primary consequence is a denial of service, where an attacker can cause the application to consume excessive CPU resources, potentially leading to application downtime.
While upgrading is the best solution, implementing input validation and using alternative data structures can serve as temporary workarounds to mitigate the risk.
References
Related vulnerabilities
Recent vulnerabilities recorded for jruby.
Follow Vulert in Google
Get more Vulert vulnerability and dependency-security updates in Google Search and AI results.