It certainly is unprofessional and opens up emotion and negative morale issues but - it isn't criminal.
I'm a Sr Exec at a publicly held company. There is so much that goes into compensation - education, experience, longevity, lateral transfers vs upward mobility, market conditions, regionality, industry, comp ranges available within a role profile, dept, or function, etc.
There are also things like more/less benefits; stock options; long-term incentive packages; bonuses; and so on.
When "word on the street" reaches me that so and so has been discussing salary and comp; I tend to ask the person speaking with me, "do you believe what they're saying?", and, "are you sure you want to know?".
Now, in your case, a published list (presumably accurate data) eliminates speculation about the source and honesty but in the end, is anyone reading it or being upset about going to change the immediate situation? No.
It might open up future discussions for role profile or position leveling - or at least lend itself to discussing compensation factors within your organization and how various attributes are weighted and rewarded.
At the very least, an acknowledgement that the data went out mistakenly and an apology is in order.