diff --git a/app/models/domain_block.rb b/app/models/domain_block.rb
index b5d1f2e0796..4fb554769dd 100644
--- a/app/models/domain_block.rb
+++ b/app/models/domain_block.rb
@@ -21,7 +21,7 @@ class DomainBlock < ApplicationRecord
   include DomainNormalizable
   include DomainMaterializable
 
-  enum :severity, { silence: 0, suspend: 1, noop: 2 }
+  enum :severity, { silence: 0, suspend: 1, noop: 2 }, validate: true
 
   validates :domain, presence: true, uniqueness: true, domain: true
 
diff --git a/db/migrate/20240220082519_fix_invalid_domain_block_severities.rb b/db/migrate/20240220082519_fix_invalid_domain_block_severities.rb
new file mode 100644
index 00000000000..ff0caac2ceb
--- /dev/null
+++ b/db/migrate/20240220082519_fix_invalid_domain_block_severities.rb
@@ -0,0 +1,17 @@
+# frozen_string_literal: true
+
+class FixInvalidDomainBlockSeverities < ActiveRecord::Migration[7.1]
+  disable_ddl_transaction!
+
+  def up
+    safety_assured do
+      execute <<~SQL.squish
+        UPDATE domain_blocks
+        SET severity = CASE WHEN severity > 2 THEN 2 WHEN severity < 0 THEN 0 END
+        WHERE severity > 2 OR severity < 0 RETURNING id;
+      SQL
+    end
+  end
+
+  def down; end
+end
diff --git a/spec/requests/api/v1/admin/domain_blocks_spec.rb b/spec/requests/api/v1/admin/domain_blocks_spec.rb
index 415281a9327..a6f3c17ea3b 100644
--- a/spec/requests/api/v1/admin/domain_blocks_spec.rb
+++ b/spec/requests/api/v1/admin/domain_blocks_spec.rb
@@ -205,6 +205,17 @@ RSpec.describe 'Domain Blocks' do
         expect(response).to have_http_status(422)
       end
     end
+
+    context 'when severity is invalid' do
+      let(:params) { { domain: 'bar.com', severity: :bar } }
+
+      it 'returns http unprocessable entity' do
+        subject
+
+        expect(response).to have_http_status(422)
+        expect(body_as_json[:error]).to eq('Validation failed: Severity is not included in the list')
+      end
+    end
   end
 
   describe 'PUT /api/v1/admin/domain_blocks/:id' do