Cool down before you install: give new gems a few days to be vetted - RubyGems Blog

Most supply-chain attacks against RubyGems exploit a narrow window: an account is compromised, a malicious version ships, and any bundle install in the minutes that follow resolves straight to it. Bundler 4.0.13 introduces cooldown, a time-based filter that refuses to resolve to a version until it has been public for at least N days. Releases too new to have been scrutinized are passed over in favor of ones that have aged past the window. .