Unfortunately this is a product not many care for nor know about, and I had a personal working relationship with this vendor, so even if it were “leaked anonymously” they could point back at me and make things a living hell.
At this point it’s been almost five years. They made their stance known. The exploit isn’t one that can be done completely remote without some internal knowledge to the setup of the equipment. It’s old news and they’re better off fading away in obscurity. I just won’t bother to try helping them make their products better and more secure.
If it makes you feel any better, you're not alone. Would be a few more hoops to jump through to connect it to me, but as far as I know my company is the only customer left using this particular piece of software. The vebdor let go all their support staff and devs for it over a year ago. It's also highly likely that my company has a significantly customized version of this software.
Files shipped with the client install include functions to not only encrypt passwords (expected) but to decrypt them as well. If anyone got into the users table of the db it's all over.
Edit: Also to be fair, I don't truly know if this would be considered a problem. If someone has the users table you're probably fucked in a lot of other ways too.
It's very responsible of you to be thinking of the poor corporation; they needed a hand from a hardworking volunteer like yourself and you did the responsible thing and made their lives easier. Hurray!
Don't release it to the public. Release it to a trusted professional with an obligation to release it to the public. "Oh no I don't have the data anymore. I gave it to X to see if they'd have better luck! convincing you!"
Mostly though, going to every possible channel and reporting publicly as a last resort is HEAVILY unlikely to result in legal action. Traditionally, I mean. Fuck if I know nowadays.