Security bugs are common in most online systems. However, a loophole in a distributed ledger can be fatal, since it can cause irreversible damage as data once confirmed is final and no one can alter it.
In Ethereum, bad coding has led to a loss of millions of dollars. Since Ripple limits the functionality on which a user can build on top of, there would be less room for vulnerabilities.
The question is, can Ripple continue to evolve without having any major security bugs?