Mozilla has made a change in Firefox that will block all of the older versions of Java that contain a critical vulnerability that’s being actively exploited. The decision to add these vulnerable versions of Java to the browser’s blocklist is designed to protect users who may not be aware of the flaw and attacks. Detailed information can be found on their blog.
Older versions of Java will now be blocked in Mozilla Firefox in order to protect against the vulnerabilities that these older versions have. Though the vulnerability was patched after being identified in February by Oracle, there will be users running outdated version of Java for Firefox.
Java plugins of version 6 update 30, version 7 update 2 are now added to Firefox blocklist to prevent them from running.
One quick way to make sure every Firefox plugin is updated is to check it’s status on Mozilla’ plugin check site.
This blocking though is a good decision by Mozilla for protecting Firefox users and hopefully prevent many systems from getting compromised.