This simple pipeline script:

def rev="v3.1.7"
echo "2"
rev.replaceAll(/v([0-9])\../)

will result in this exception after printing "2":

org.jenkinsci.plugins.scriptsecurity.sandbox.RejectedAccessException: unclassified method java.lang.String replaceAll java.lang.String
at org.jenkinsci.plugins.scriptsecurity.sandbox.groovy.SandboxInterceptor.onMethodCall(SandboxInterceptor.java:113)
at org.kohsuke.groovy.sandbox.impl.Checker$1.call(Checker.java:149)

However the sandbox administration area doesn't offer to add this violation to the whitebox.