Mechanism of the formation of peracetic acid Wikipedia says that the equilibrium $$\ce{H2O2 + CH3COOH ⇌ CH3COOOH + H2O}$$ occurs. What is its mechanism?
The following is my speculation.  

The first possibility is that $\ce{CH3COOH}$ is protonated into $\ce{CH3CO(OH2)+}$ because of the strong acid condition and then turns into $\ce{CH3C+O}$. Because the oxygen atom in $\ce{H2O2}$ is electron rich, it will bond with the carbon atom with positive charge to form $\ce{CH3C(=O)O(OH+)H}$ and then peracetic acid is formed by deprotonation.
The second one is that the oxygen atom in $\ce{H2O2}$ attacks the carbon atom in $\ce{MeCOOH}$, then the $\ce{OH}$ in $\ce{COOH}$ and 
one of the $\ce H$ in $\ce {H2O2}$ leave.  

Is the mechanism above right or not? If it is not, what's the correct one?

P.S. (this question does not answer my question)
You are not too far off. It is somewhat of a mixture of the two mechanisms you proposed. The carbonyl oxygen is much more basic than the non-carbonyl oxygen and will be protonated preferentially. Then hydrogen peroxide can attack, and once the tetrahedral intermediate collapses, deprotonation yields peracetic acid.