diff --git a/lib/net/imap/command_data.rb b/lib/net/imap/command_data.rb
index 9a5749b5..f97fda44 100644
--- a/lib/net/imap/command_data.rb
+++ b/lib/net/imap/command_data.rb
@@ -212,7 +212,7 @@ def send_data(imap, tag) = data.each do _1.send_data(imap, tag) end
 
       def validate
         return unless data.last in RawText(data: text)
-        if text.rindex(/~?\{[1-9]\d*\+?\}\z/n)
+        if text.rindex(/\{\d+\+?\}\z/n)
           raise DataFormatError, "RawData cannot end with literal continuation"
         end
       end
diff --git a/test/net/imap/test_command_data.rb b/test/net/imap/test_command_data.rb
index 59419899..4d5ab858 100644
--- a/test/net/imap/test_command_data.rb
+++ b/test/net/imap/test_command_data.rb
@@ -366,6 +366,13 @@ class RawDataTest < CommandDataTest
       assert_raise(DataFormatError) do RawData.new(data: "~literal+ ~{123+}") end
       raw = RawData.new(data: " {123} ")
       assert_equal [RawText[" {123} "]], raw.data
+
+      assert_raise(DataFormatError) do RawData.new(data: "literal {0}") end
+      assert_raise(DataFormatError) do RawData.new(data: "literal+ {0+}") end
+      assert_raise(DataFormatError) do RawData.new(data: "~literal ~{0}") end
+      assert_raise(DataFormatError) do RawData.new(data: "~literal+ ~{0+}") end
+      raw = RawData.new(data: " {0} ")
+      assert_equal [RawText[" {0} "]], raw.data
     end
 
     data(