Is risk aversion bounded in CRRA utility? For instance, Cagetti (2003) estimates ρ > 2 by targeting the median wealth of households,
Gourinchas and Parker (2002) find ρ &lt; 2 by targeting the mean consumption of households,
Chetty (2006), using the effects of wage changes on labor supply, finds that ρ &lt; 2.

Marginal utility of consumption is decreasing very fast when ρ > 2, still you can find in macro or finance even ρ = 10. In experimental or in labor ρ is close to 0.

Is there any bound on this coefficient?
A practical or mathematical bound? For a practical bound, people have argued that very large values of $\rho$ are impossible to reconcile with non-financial risk taking. Indeed, some values of $\rho$ may not be compatible with crossing the street. 

Perhaps that's a bit glib, but consider Neilson and Winter (2001) which find that CRRA utility and observed wage premia for dangerous jobs are compatible with values of $\rho$ such that  $0&lt;\rho&lt;&lt;1$. They then point out that if $\rho$ were very very large and the model properly specified then the dangerous job wage premium would also be large or alternatively (and implausibly) that people place a very, very low value on their own lives (like $3,000). 

Generally speaking, data and models implying very high values of $\rho$ like a basic equity premium setup and the relative volatility of equity returns and consumption) are often taken as signs of model miss-specification instead of alternative measures of risk preferences. 

While we can't talk about globally infinite risk aversion, we can consider what happens as If you take the limit $\rho\rightarrow\infty$ around a particular value of wealth $W_0$. As it goes to infinity you get a step-function utility function with $U(W) = -\infty, W &lt; W_0$ and $U(W) = C, W \ge W_0$.