The official response (so far) is "We’ve examined our servers and are updating them to protect against the vulnerability. Customer data appears unaffected."

Is this adequately reassuring to other Mint users?

Boilerplate/automated responses are rarely helpful and often the single most frustrating thing in the technical support/customer support world. I would truly wish on technical forums (like Mint, and Microsoft, etc.) that they would be done away with.

The complete lack of emotionality and disconnect it creates with your user base is damning to your company. The only automated response I want to hear is "Your ticket was forwarded to XYZ, if there is no response within 24 hours please contact thisperson@ourcompany.com".

I really feel that customer/technical support is a BIG part of keeping customers/getting repeat customers/selling via word of mouth. And its so often tossed to the way side.