diff --git a/test/ruby/test_exception.rb b/test/ruby/test_exception.rb
index 6955118de7..ecbf042e49 100644
--- a/test/ruby/test_exception.rb
+++ b/test/ruby/test_exception.rb
@@ -1080,4 +1080,15 @@ $stderr = $stdout; raise "\x82\xa0"') do |outs, errs, status|
       }
     end;
   end
+
+  def test_break_in_once
+    assert_separately([], "#{<<-"begin;"}\n#{<<~'end;'}")
+    begin;
+      obj = Object.new
+      def obj.try
+        /#{break}/o
+      end
+      assert_raise(LocalJumpError, /proc-closure/) {obj.try}
+    end;
+  end
 end
diff --git a/vm_insnhelper.c b/vm_insnhelper.c
index 35684e6ed1..eea16d730e 100644
--- a/vm_insnhelper.c
+++ b/vm_insnhelper.c
@@ -1083,13 +1083,13 @@ vm_throw_start(rb_thread_t *const th, rb_control_frame_t *const reg_cfp, enum ru
 
 	    while (escape_cfp < eocfp) {
 		if (escape_cfp->ep == ep) {
-		    const VALUE epc = escape_cfp->pc - escape_cfp->iseq->body->iseq_encoded;
-		    const rb_iseq_t * const iseq = escape_cfp->iseq;
-		    const struct iseq_catch_table * const ct = iseq->body->catch_table;
-		    const int ct_size = ct->size;
-		    int i;
+		    const rb_iseq_t *const iseq = escape_cfp->iseq;
+		    const VALUE epc = escape_cfp->pc - iseq->body->iseq_encoded;
+		    const struct iseq_catch_table *const ct = iseq->body->catch_table;
+		    unsigned int i;
 
-		    for (i=0; i<ct_size; i++) {
+		    if (!ct) break;
+		    for (i=0; i < ct->size; i++) {
 			const struct iseq_catch_table_entry * const entry = &ct->entries[i];
 
 			if (entry->type == CATCH_TYPE_BREAK &&