You're close vbresults but you're missing the nitty-gritty per say, I was there and reporting to them about that exploit and also furious at them too when all this was going down

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People lost trust in it, that one exploit (can't remember the exact exploit i.e. not sure if it was the filestore one or not) was reported to them, their staff patched it on the site that reported the find and had planned to include the patch in the next release however that never happened and therefor
a known exploit remained in the product through several variations of it over the course of one year give or take a month or two until the same exact forum owner was hacked again, he went to investigate and realized they had never included the original fix in the product... he had been hacked again by overwriting files that had the fix in it, with new fresh files that had the exploitable code still within well over a year later - I remember his comments and he was shocked to find that was how he was hacked again! vBSEO dropped not only the ball but the chain, the hook, and the crane it was attached to seemingly into the bottom of the ocean.
vBSEO was still alive for a while after that however to me, I noticed the decline right after that fiasco revealed itself. Their own site was infected, their download system also compromised from what I recall... so with that said I've seen a few asking for copies of vBSEO "I was licensed, I should be able to use a copy if I find it they left me hanging" or similar... well good luck hoping the copy you find even if from a friend was not already infected to begin with, might want to consider that based on the fact their site was compromised at one point in time, think of how many members were downloading files during that timeframe

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To this day I'm still fixing sites and the owners asking me "do you know how this happened" and in the footer is Search Engine Friendly URLs by vBSEO 3.6.0 or Search Engine Friendly URLs by vBSEO 3.6.1

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