Official Mastodon account of the JRuby Team
JRuby 10.1 is released! We've caught up with CRuby 4.0 after less than four months, and pushed a bunch of new optimizations: smaller objects, smaller numerics, and groundwork for new string, array, and hash implementations. We'll maintain 10.0 as our stable line, but do try 10.1 yourself!
JRuby 10.0.5.0 is released! This round we fixed some memory leaks when embedding multiple JRuby instances, a few pesky Windows bugs, and several Ruby compatibility blockers. Enjoy!
https://www.jruby.org/2026/04/06/jruby-10-0-5-0
Earlier today the JRuby team was informed of a low-severity vulnerability in the bcrypt-ruby gem. We worked with the library's maintainers to arrange a fix and disclosure. The issue is now fixed in versions 3.1.22 and higher. Exposure risk is low, but upgrading is recommended.
CVE-2026-33306: Integer Overflow Causes Zero Key-Strengthening Iterations at Cost=31 on JRuby
https://github.com/bcrypt-ruby/bcrypt-ruby/security/advisories/GHSA-f27w-vcwj-c954
JRuby 10.0.4.0 is released! A month after 10.0.3.0, we've addressed lots of one-off issues, a few memory and thread-safety fixes, and general compatibility and stabilization work. Enjoy!
https://www.jruby.org/2026/03/04/jruby-10-0-4-0.html
JRuby 10.0.3.0 is released! Over 80 issues and pull requests and 13 external contributors combined to help further stabilize our 10.0 series! There's lots of compatibility fixes, a few performance enhancements, and a number of library updates. Upgrading is recommended!
Warbler 2.1.0 has been released! Warbler allows you to package JRuby applications as a single binary, either a .jar file you can run directly or a .war file you can deploy to any Java application server. There's even options to precompile your code to obfuscate it... many users out there ship commercial JRuby apps this way. Blog post coming!
We have published Docker images for JRuby 9.4 and JRuby 10 on JDK 25! The -dev images are also updated to latest commits. Give them a try and let us know if there's any issues!
JRuby 9.4.14.0 is released! We've updated a bunch of the standard library (including "cgi" to fix a couple of CVEs), fixed a few memory leaks and a bunch of compatibility issues, and generally stabilized things. Upgrading is recommended!
JRuby 10.0.2.0 is released! This is a small release to fix an ArgumentError regression in JRuby 10.0.1.0 plus a few other small fixes. Recommended upgrade for all, but let us know if you run into any issues!
https://www.jruby.org/2025/08/07/jruby-10-0-2-0.html
We have just released JRuby 10.0.1.0, our first update to JRuby 10! There's dozens of patches including full support (finally) for Zeitwerk and a bunch of Ruby 3.4 language fixes. Upgrade today and let us know how it goes!
We have released jruby-maven-plugins 3.0.6, which updates JRuby to 9.4.13.0 along with several other improvements. But more exciting: Warbler is BACK! We've updated it for latest JRuby and dependencies and it's running green in CI. Time for feature requests!
https://github.com/jruby/warbler/issues/558#issuecomment-3002560812
FYI: now that Ubuntu 20.04 is EOL, future releases of the JRuby Docker image will be based on Ubuntu 22.04.
This will take effect with releases 9.4.14.0 and 10.0.1.0, whenever they happen.
See https://github.com/docker-library/official-images/pull/19167
JRuby 9.4.13.0 is released! We have fixed several user issues, including a slow leak in Java interface implementation, a possible deadlock between JIT and main threads, and backported launcher improvements from JRuby 10!
https://www.jruby.org/2025/06/10/jruby-9-4-13-0.html
Security advisory: We have released jruby-openssl gem 0.15.4, jruby 10.0.0.1, and jruby 9.4.12.1 to address CVE-2025-46551, disabled hostname verification by default, which may allow certificates to verify from improper domains. We recommend that all users upgrade!
https://www.cve.org/CVERecord?id=CVE-2025-46551