All software has bugs, and the subset of bugs which turn out to be security vulnerabilities is borderline asymptotic.
That's not to say all frameworks are created equally secure, but the differences have more to do with the culture around the project than any technical decisions (minus some very specific language-related issues).
Rails is a big, public project; with many years now of being used by a sizable number of people. There will be more security vulnerabilities discovered, hopefully they'll be addressed quickly and communicated well (which this one seems to be).
That's a long-winded way of saying to be cautious with picking some other framework because it has less security vulnerabilities reported, that almost certainly has no bearing on it being more secure.
That's not to say all frameworks are created equally secure, but the differences have more to do with the culture around the project than any technical decisions (minus some very specific language-related issues).
Rails is a big, public project; with many years now of being used by a sizable number of people. There will be more security vulnerabilities discovered, hopefully they'll be addressed quickly and communicated well (which this one seems to be).
That's a long-winded way of saying to be cautious with picking some other framework because it has less security vulnerabilities reported, that almost certainly has no bearing on it being more secure.