Mozilla has made first beta of Firefox 26 available for Windows, Mac and Linux with Click to Play Plugins which means this browser version and future versions of Firefox won’t activate all plugins by default except for latest version of Flash.

" When a site tries to use a plugin, the user will be able to choose whether to enable the plugin on that site. Outdated plugins are a big source of security vulnerabilities so this feature will ensure users are safe and Firefox runs smoothly. The Flash plugin will remain enabled by default." said  Mozilla in a blog post.

Firefox 26 beta
We’ve a remedy for that, read how to set  a Particular Plugin to “Always Activate” or “Never Activate” State from Firefox 26 onwards.

You can download Firefox beta from here, check the release notes if interested.