Linux Flash player nowhere near version 19.x
For some inexplicable reason, years ago Adobe decided that there'd be no new major versions of their Flash Player for Linux after 11.x. It's a strange decision because they are still patching 11.x anyway because it too has a shed-load of vulnerabilities. Note that Google Chrome for Linux does indeed include Flash Player 19.x (embedded into the browser) via a sneaky deal between Google and Adobe no doubt involving large brown envelopes of cash.
They did a similar "we're not doing any more major versions" trick with the Android Flash player, but have dubiously refused to update it for security fixes since it was frozen at 11.1.115.81 a full two years ago! So if you prefer Android Firefox and want to see Flash content, you're stuck with a version that probably has 200+ vulnerabilities in it - way to go Adobe.