diff --git a/package-lock.json b/package-lock.json
index 49acf29c3b..582ae772a8 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -5939,7 +5939,8 @@
 				},
 				"kind-of": {
 					"version": "6.0.2",
-					"resolved": "",
+					"resolved": "https://registry.npmjs.org/kind-of/-/kind-of-6.0.2.tgz",
+					"integrity": "sha512-s5kLOcnH0XqDO+FvuaLX8DDjZ18CGFk7VygH40QoKPUQhW4e2rvM0rwUq0t8IQDOwYSeLK01U90OjzBTme2QqA==",
 					"dev": true
 				}
 			}
@@ -10566,7 +10567,8 @@
 				},
 				"kind-of": {
 					"version": "6.0.2",
-					"resolved": "",
+					"resolved": "https://registry.npmjs.org/kind-of/-/kind-of-6.0.2.tgz",
+					"integrity": "sha512-s5kLOcnH0XqDO+FvuaLX8DDjZ18CGFk7VygH40QoKPUQhW4e2rvM0rwUq0t8IQDOwYSeLK01U90OjzBTme2QqA==",
 					"dev": true
 				}
 			}
@@ -23584,7 +23586,8 @@
 				},
 				"kind-of": {
 					"version": "6.0.2",
-					"resolved": "",
+					"resolved": "https://registry.npmjs.org/kind-of/-/kind-of-6.0.2.tgz",
+					"integrity": "sha512-s5kLOcnH0XqDO+FvuaLX8DDjZ18CGFk7VygH40QoKPUQhW4e2rvM0rwUq0t8IQDOwYSeLK01U90OjzBTme2QqA==",
 					"dev": true
 				}
 			}
diff --git a/src/wp-includes/rest-api/endpoints/class-wp-rest-block-renderer-controller.php b/src/wp-includes/rest-api/endpoints/class-wp-rest-block-renderer-controller.php
index 3388078d05..07a389e794 100644
--- a/src/wp-includes/rest-api/endpoints/class-wp-rest-block-renderer-controller.php
+++ b/src/wp-includes/rest-api/endpoints/class-wp-rest-block-renderer-controller.php
@@ -70,6 +70,22 @@ class WP_REST_Block_Renderer_Controller extends WP_REST_Controller {
 
 								return rest_validate_value_from_schema( $value, $schema );
 							},
+							'sanitize_callback' => static function ( $value, $request ) {
+								$block = WP_Block_Type_Registry::get_instance()->get_registered( $request['name'] );
+
+								if ( ! $block ) {
+									// This will get rejected in ::get_item().
+									return true;
+								}
+
+								$schema = array(
+									'type'                 => 'object',
+									'properties'           => $block->get_attributes(),
+									'additionalProperties' => false,
+								);
+
+								return rest_sanitize_value_from_schema( $value, $schema );
+							},
 						),
 						'post_id'    => array(
 							'description' => __( 'ID of the post context.' ),
diff --git a/tests/phpunit/tests/rest-api/rest-block-renderer-controller.php b/tests/phpunit/tests/rest-api/rest-block-renderer-controller.php
index 423d4a4947..94c7cf8103 100644
--- a/tests/phpunit/tests/rest-api/rest-block-renderer-controller.php
+++ b/tests/phpunit/tests/rest-api/rest-block-renderer-controller.php
@@ -55,6 +55,15 @@ class REST_Block_Renderer_Controller_Test extends WP_Test_REST_Controller_Testca
 	 */
 	protected static $non_dynamic_block_name = 'core/non-dynamic';
 
+	/**
+	 * Dynamic block with boolean attributes block name.
+	 *
+	 * @since 5.5.0
+	 *
+	 * @var string
+	 */
+	protected static $dynamic_block_with_boolean_attributes_block_name = 'core/dynamic-block-with-boolean-attributes';
+
 	/**
 	 * Test API user's ID.
 	 *
@@ -127,6 +136,7 @@ class REST_Block_Renderer_Controller_Test extends WP_Test_REST_Controller_Testca
 		$this->register_test_block();
 		$this->register_post_context_test_block();
 		$this->register_non_dynamic_block();
+		$this->register_dynamic_block_with_boolean_attributes();
 		parent::setUp();
 	}
 
@@ -139,6 +149,7 @@ class REST_Block_Renderer_Controller_Test extends WP_Test_REST_Controller_Testca
 		WP_Block_Type_Registry::get_instance()->unregister( self::$block_name );
 		WP_Block_Type_Registry::get_instance()->unregister( self::$context_block_name );
 		WP_Block_Type_Registry::get_instance()->unregister( self::$non_dynamic_block_name );
+		WP_Block_Type_Registry::get_instance()->unregister( self::$dynamic_block_with_boolean_attributes_block_name );
 		parent::tearDown();
 	}
 
@@ -195,6 +206,30 @@ class REST_Block_Renderer_Controller_Test extends WP_Test_REST_Controller_Testca
 		register_block_type( self::$non_dynamic_block_name );
 	}
 
+	/**
+	 * Registers the dynamic with boolean attributes block name.
+	 *
+	 * @since 5.5.0
+	 */
+	protected function register_dynamic_block_with_boolean_attributes() {
+		register_block_type(
+			self::$dynamic_block_with_boolean_attributes_block_name,
+			array(
+				'attributes'      => array(
+					'boolean_true_attribute'  => array(
+						'type'    => 'boolean',
+						'default' => true,
+					),
+					'boolean_false_attribute' => array(
+						'type'    => 'boolean',
+						'default' => false,
+					),
+				),
+				'render_callback' => array( $this, 'render_test_block' ),
+			)
+		);
+	}
+
 	/**
 	 * Test render callback.
 	 *
@@ -522,6 +557,33 @@ class REST_Block_Renderer_Controller_Test extends WP_Test_REST_Controller_Testca
 		$this->assertErrorResponse( 'block_invalid', $response, 404 );
 	}
 
+	/**
+	 * @ticket 50620
+	 */
+	public function test_get_sanitized_attributes_for_dynamic_block_with_boolean_attributes() {
+		wp_set_current_user( self::$user_id );
+
+		$request = new WP_REST_Request( 'GET', self::$rest_api_route . self::$dynamic_block_with_boolean_attributes_block_name );
+
+		$attributes = array(
+			'boolean_true_attribute'  => 'true',
+			'boolean_false_attribute' => 'false',
+		);
+
+		$expected = array(
+			'boolean_true_attribute'  => true,
+			'boolean_false_attribute' => false,
+		);
+
+		$request->set_param( 'context', 'edit' );
+		$request->set_param( 'attributes', $attributes );
+		$response = rest_get_server()->dispatch( $request );
+		$this->assertEquals( 200, $response->get_status() );
+		$data = $response->get_data();
+
+		$this->assertSame( $expected, json_decode( $data['rendered'], true ) );
+	}
+
 	/**
 	 * Get item schema.
 	 *