diff --git a/core/app/models/spree/log_entry.rb b/core/app/models/spree/log_entry.rb
index 2e3bd32a456..2334c3658b5 100644
--- a/core/app/models/spree/log_entry.rb
+++ b/core/app/models/spree/log_entry.rb
@@ -2,10 +2,83 @@
 
 module Spree
   class LogEntry < Spree::Base
+    # Classes used in core that can be present in serialized details
+    #
+    # Users can add their own classes in
+    # `Spree::Config#log_entry_permitted_classes`.
+    #
+    # @see Spree::AppConfiguration#log_entry_permitted_classes
+    CORE_PERMITTED_CLASSES = [
+      ActiveMerchant::Billing::Response,
+      ActiveSupport::TimeWithZone,
+      Time,
+      ActiveSupport::TimeZone
+    ].freeze
+
+    # Raised when a disallowed class is tried to be loaded
+    class DisallowedClass < RuntimeError
+      attr_reader :psych_exception
+
+      def initialize(psych_exception:)
+        @psych_exception = psych_exception
+        super(default_message)
+      end
+
+      private
+
+      def default_message
+        <<~MSG
+          #{psych_exception.message}
+
+          You can specify custom classes to be loaded in config/initializers/spree.rb. E.g:
+
+          Spree.config do |config|
+            config.log_entry_permitted_classes = ['MyClass']
+          end
+        MSG
+      end
+    end
+
+    # Raised when YAML contains aliases and they're not enabled
+    class BadAlias < RuntimeError
+      attr_reader :psych_exception
+
+      def initialize(psych_exception:)
+        @psych_exception = psych_exception
+        super(default_message)
+      end
+
+      private
+
+      def default_message
+        <<~MSG
+          #{psych_exception.message}
+
+          You can explicitly enable aliases in config/initializers/spree.rb. E.g:
+
+          Spree.config do |config|
+            config.log_entry_allow_aliases = true
+          end
+        MSG
+      end
+    end
+
+    def self.permitted_classes
+      CORE_PERMITTED_CLASSES + Spree::Config.log_entry_permitted_classes.map(&:constantize)
+    end
+
     belongs_to :source, polymorphic: true, optional: true
 
     def parsed_details
-      @details ||= YAML.load(details)
+      @details ||= YAML.safe_load(
+        details,
+        permitted_classes: self.class.permitted_classes,
+        aliases: Spree::Config.log_entry_allow_aliases
+      )
+    rescue Psych::DisallowedClass => e
+      raise DisallowedClass.new(psych_exception: e)
+    rescue Psych::BadAlias => e
+      raise BadAlias.new(psych_exception: e)
     end
   end
 end
diff --git a/core/lib/spree/app_configuration.rb b/core/lib/spree/app_configuration.rb
index e0276aa5ac1..9d9dada2709 100644
--- a/core/lib/spree/app_configuration.rb
+++ b/core/lib/spree/app_configuration.rb
@@ -165,6 +165,22 @@ class AppConfiguration < Preferences::Configuration
     #   @return [String] URL of logo used on frontend (default: +'logo/solidus.svg'+)
     preference :logo, :string, default: 'logo/solidus.svg'
 
+    # @!attribute [rw] log_entry_permitted_classes
+    #   @return [Array<String>] An array of extra classes that are allowed to be
+    #     loaded from a serialized YAML as details in {Spree::LogEntry}
+    #     (defaults to a non-frozen empty array, so that extensions can add
+    #     their own classes).
+    #   @example
+    #     config.log_entry_permitted_classes = ['Date']
+    preference :log_entry_permitted_classes, :array, default: []
+
+    # @!attribute [rw] log_entry_allow_aliases
+    #   @return [Boolean] Whether YAML aliases are allowed when loading
+    #     serialized data in {Spree::LogEntry}. It defaults to true. Depending
+    #     on the source of your data, you may consider disabling it to prevent
+    #     entity expansion attacks.
+    preference :log_entry_allow_aliases, :boolean, default: true
+
     # @!attribute [rw] mails_from
     #   @return [String] Email address used as +From:+ field in transactional emails.
     preference :mails_from, :string, default: 'solidus@example.com'
diff --git a/core/lib/spree/core/engine.rb b/core/lib/spree/core/engine.rb
index d8a63235984..022463d1a25 100644
--- a/core/lib/spree/core/engine.rb
+++ b/core/lib/spree/core/engine.rb
@@ -15,6 +15,12 @@ class Engine < ::Rails::Engine
         generator.test_framework :rspec
       end
 
+      if ActiveRecord.respond_to?(:yaml_column_permitted_classes) || ActiveRecord::Base.respond_to?(:yaml_column_permitted_classes)
+        config.active_record.yaml_column_permitted_classes ||= []
+        config.active_record.yaml_column_permitted_classes |=
+          [Symbol, BigDecimal, ActiveSupport::HashWithIndifferentAccess]
+      end
+
       initializer "spree.environment", before: :load_config_initializers do |app|
         app.config.spree = Spree::Config.environment
       end
diff --git a/core/solidus_core.gemspec b/core/solidus_core.gemspec
index 30871b7bc84..42c3ba3f08a 100644
--- a/core/solidus_core.gemspec
+++ b/core/solidus_core.gemspec
@@ -40,6 +40,7 @@ Gem::Specification.new do |s|
   s.add_dependency 'mini_magick', '~> 4.10'
   s.add_dependency 'monetize', '~> 1.8'
   s.add_dependency 'kt-paperclip', '~> 6.3'
+  s.add_dependency 'psych', ['>= 3.1.0', '< 5.0']
   s.add_dependency 'ransack', '~> 2.0'
   s.add_dependency 'state_machines-activerecord', '~> 0.6'
 
diff --git a/core/spec/models/spree/log_entry_spec.rb b/core/spec/models/spree/log_entry_spec.rb
new file mode 100644
index 00000000000..c9ae45d650f
--- /dev/null
+++ b/core/spec/models/spree/log_entry_spec.rb
@@ -0,0 +1,56 @@
+# frozen_string_literal: true
+
+require 'rails_helper'
+
+RSpec.describe Spree::LogEntry, type: :model do
+  describe '#parsed_details' do
+    it 'allow aliases by default' do
+      x = []
+      x << x
+
+      log_entry = described_class.new(details: x.to_yaml)
+
+      expect { log_entry.parsed_details }.not_to raise_error
+    end
+
+    it 'can disable aliases and raises a meaningful exception when used' do
+      stub_spree_preferences(log_entry_allow_aliases: false)
+      x = []
+      x << x
+
+      log_entry = described_class.new(details: x.to_yaml)
+
+      expect { log_entry.parsed_details }.to raise_error(described_class::BadAlias, /log_entry_allow_aliases/)
+    end
+
+    it 'can parse ActiveMerchant::Billing::Response instances' do
+      response = ActiveMerchant::Billing::Response.new('success', 'message')
+
+      log_entry = described_class.new(details: response.to_yaml)
+
+      expect { log_entry.parsed_details }.not_to raise_error
+    end
+
+    it 'can parse ActiveSupport::TimeWithZone instances' do
+      time = Time.zone.now
+
+      log_entry = described_class.new(details: time.to_yaml)
+
+      expect { log_entry.parsed_details }.not_to raise_error
+    end
+
+    it 'can parse user specified classes instances' do
+      stub_spree_preferences(log_entry_permitted_classes: ['Date'])
+
+      log_entry = described_class.new(details: Date.today)
+
+      expect { log_entry.parsed_details }.not_to raise_error
+    end
+
+    it 'raises a meaningful exception when a disallowed class is found' do
+      log_entry = described_class.new(details: Date.today)
+
+      expect { log_entry.parsed_details }.to raise_error(described_class::DisallowedClass, /log_entry_permitted_classes/)
+    end
+  end
+end
diff --git a/core/spec/models/spree/promotion/rules/user_role_spec.rb b/core/spec/models/spree/promotion/rules/user_role_spec.rb
index 9dbbabe2408..baba3f51609 100644
--- a/core/spec/models/spree/promotion/rules/user_role_spec.rb
+++ b/core/spec/models/spree/promotion/rules/user_role_spec.rb
@@ -3,7 +3,7 @@
 require 'rails_helper'
 
 RSpec.describe Spree::Promotion::Rules::UserRole, type: :model do
-  let(:rule) { described_class.new(preferred_role_ids: roles_for_rule) }
+  let(:rule) { described_class.new(preferred_role_ids: roles_for_rule.map(&:id)) }
   let(:user) { create(:user, spree_roles: roles_for_user) }
   let(:roles_for_rule) { [] }
   let(:roles_for_user) { [] }