diff --git a/CHANGELOG.md b/CHANGELOG.md
index 48cc0484e3b0..d824a6177f8a 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -2,6 +2,10 @@
 
 ## master (unreleased)
 
+### Bug fixes
+
+* [#6699](https://github.com/rubocop-hq/rubocop/issues/6699): Fix infinite loop for `Layout/IndentationWidth` and `Layout/IndentationConsistency` when bad modifier indentation before good method definition. ([@koic][])
+
 ### Changes
 
 * [#6688](https://github.com/rubocop-hq/rubocop/pull/6688): Add `iterator?` to deprecated methods and prefer `block_given?` instead. ([@tejasbubane][])
diff --git a/lib/rubocop/cop/layout/indentation_width.rb b/lib/rubocop/cop/layout/indentation_width.rb
index 99b80b6b51db..8740f746d5f5 100644
--- a/lib/rubocop/cop/layout/indentation_width.rb
+++ b/lib/rubocop/cop/layout/indentation_width.rb
@@ -54,6 +54,10 @@ class IndentationWidth < Cop # rubocop:disable Metrics/ClassLength
 
         SPECIAL_MODIFIERS = %w[private protected].freeze
 
+        def_node_matcher :access_modifier?, <<-PATTERN
+          [(send ...) access_modifier?]
+        PATTERN
+
         def on_rescue(node)
           _begin_node, *_rescue_nodes, else_node = *node
           check_indentation(node.loc.else, else_node)
@@ -161,15 +165,12 @@ def autocorrect(node)
         private
 
         def check_members(base, members)
-          check_indentation(base, members.first)
+          check_indentation(base, select_check_member(members.first))
 
           return unless members.any? && members.first.begin_type?
 
           if indentation_consistency_style == 'rails'
-            each_member(members) do |member, previous_modifier|
-              check_indentation(previous_modifier, member,
-                                indentation_consistency_style)
-            end
+            check_members_for_rails_style(members)
           else
             members.first.children.each do |member|
               next if member.send_type? && member.access_modifier?
@@ -179,6 +180,23 @@ def check_members(base, members)
           end
         end
 
+        def select_check_member(member)
+          return unless member
+
+          if access_modifier?(member.children.first)
+            member.children.first
+          else
+            member
+          end
+        end
+
+        def check_members_for_rails_style(members)
+          each_member(members) do |member, previous_modifier|
+            check_indentation(previous_modifier, member,
+                              indentation_consistency_style)
+          end
+        end
+
         def each_member(members)
           previous_modifier = nil
           members.first.children.each do |member|
diff --git a/spec/rubocop/cli/cli_autocorrect_spec.rb b/spec/rubocop/cli/cli_autocorrect_spec.rb
index ed4d845894cd..2a6407fea748 100644
--- a/spec/rubocop/cli/cli_autocorrect_spec.rb
+++ b/spec/rubocop/cli/cli_autocorrect_spec.rb
@@ -986,12 +986,18 @@ class Dsl
       #{e}:1:1: C: Style/Documentation: Missing top-level class documentation comment.
       #{e}:2:1: C: [Corrected] Layout/AccessModifierIndentation: Indent access modifiers like `private`.
       #{e}:2:1: C: [Corrected] Layout/EmptyLinesAroundAccessModifier: Keep a blank line after `private`.
+      #{e}:2:1: C: [Corrected] Layout/IndentationWidth: Use 2 (not 0) spaces for indentation.
+      #{e}:2:1: C: [Corrected] Layout/IndentationWidth: Use 2 (not 4) spaces for indentation.
       #{e}:2:3: W: Lint/UselessAccessModifier: Useless `private` access modifier.
+      #{e}:2:5: C: [Corrected] Layout/AccessModifierIndentation: Indent access modifiers like `private`.
       #{e}:3:7: C: [Corrected] Style/MutableConstant: Freeze mutable objects assigned to constants.
       #{e}:3:7: C: [Corrected] Style/WordArray: Use `%w` or `%W` for an array of words.
       #{e}:3:8: C: [Corrected] Style/StringLiterals: Prefer single-quoted strings when you don't need string interpolation or special symbols.
       #{e}:3:15: C: [Corrected] Style/StringLiterals: Prefer single-quoted strings when you don't need string interpolation or special symbols.
       #{e}:3:21: C: [Corrected] Style/TrailingCommaInArrayLiteral: Avoid comma after the last item of an array.
+      #{e}:4:1: C: [Corrected] Layout/IndentationWidth: Use 2 (not 4) spaces for indentation.
+      #{e}:4:3: C: [Corrected] Layout/IndentationConsistency: Inconsistent indentation detected.
+      #{e}:4:5: C: [Corrected] Layout/IndentationConsistency: Inconsistent indentation detected.
       #{e}:4:7: C: [Corrected] Style/WordArray: Use `%w` or `%W` for an array of words.
     RESULT
   end
diff --git a/spec/rubocop/cop/layout/indentation_width_spec.rb b/spec/rubocop/cop/layout/indentation_width_spec.rb
index aeb911d3cc9f..9aef71ff16e7 100644
--- a/spec/rubocop/cop/layout/indentation_width_spec.rb
+++ b/spec/rubocop/cop/layout/indentation_width_spec.rb
@@ -1072,6 +1072,28 @@ def f
             end
           RUBY
         end
+
+        it 'registers an offense and corrects for bad modifier indentation ' \
+           'before good method definition' do
+          expect_offense(<<-RUBY.strip_indent)
+            class Foo
+                  private
+            ^^^^^^ Use 2 (not 6) spaces for indentation.
+
+              def foo
+              end
+            end
+          RUBY
+
+          expect_correction(<<-RUBY.strip_indent)
+            class Foo
+              private
+
+              def foo
+              end
+            end
+          RUBY
+        end
       end
 
       context 'when consistency style is normal' do