Ugh, Adobe! Flash is just about to die why do they need to put a chokehold on distribution when all we want is an update for their security hole ridden POS...
Anyway... so when you apply it should be in the email, you go here:
Then it asks for a login, the link for Flash is: https://fpdownload.macromedia.com/get/flashplayer/distyfp/current/mac/install_flash_player_24_osx_pkg.dmg
However this must work by session cookie as that URL does not work if you try via curl or after restarting browser... even pasting it in doesn't work (it takes you to the distirbution5.html), it will download if you paste in URL field and press Option-Return (and provided you have authenticated)
Yeah, I was totally using https://fpdownload.macromedia.com/get/flashplayer/current/licensing/mac/install_flash_player_XX_osx_pkg.dmg but that seems to have finally bit the dust... their older scheme was sending you an long "Adobe Distribution Auth Token" as I called it, you could curl that down and it then had unique links for your Auth token... it was scriptable... now it is not AFAIK.