diff --git a/cmd/db_diff.go b/cmd/db_diff.go
index 2bef9ce22d7..6f81455e95c 100644
--- a/cmd/db_diff.go
+++ b/cmd/db_diff.go
@@ -2,7 +2,6 @@ package cmd
 
 import (
 	"fmt"
-	"net/url"
 	"os"
 
 	"github.com/spf13/cobra"
@@ -35,7 +34,7 @@ func init() {
 	dbCmd.AddCommand(dbDiffCmd)
 }
 
-func startDBDiffCmd(dbURL []*url.URL, deleteDatabases bool) <-chan error {
+func startDBDiffCmd(base string, target string, deleteDatabases bool) <-chan error {
 	errs := make(chan error)
 	go func() {
 		defer close(errs)
@@ -45,10 +44,12 @@ func startDBDiffCmd(dbURL []*url.URL, deleteDatabases bool) <-chan error {
 			return
 		}
 
-		baseURL := dbURL[0]
-		targetURL := dbURL[1]
+		if err := d.SetBaseDB(base); err != nil {
+			errs <- err
+			return
+		}
 
-		if err := d.DownloadDatabases(baseURL, targetURL); err != nil {
+		if err := d.SetTargetDB(target); err != nil {
 			errs <- err
 			return
 		}
@@ -96,27 +97,29 @@ func runDBDiffCmd(cmd *cobra.Command, args []string) error {
 		return err
 	}
 
-	var dbURL []*url.URL
+	var base, target string
 
-	if len(args) < 2 {
+	switch len(args) {
+	case 0:
 		log.Info("base_db_url and target_db_url not provided; fetching most recent")
-		dbURL, err = getDefaultURL()
+		base, target, err = getDefaultURLs()
 		if err != nil {
-			return fmt.Errorf("could not fetch most recent database URL: %w", err)
+			return err
 		}
-	} else {
-		for _, arg := range args {
-			u, err := url.Parse(arg)
-			if err != nil {
-				return fmt.Errorf("url argument is malformed: %w", err)
-			}
-
-			dbURL = append(dbURL, u)
+	case 1:
+		log.Info("target_db_url not provided; fetching most recent")
+		base = args[0]
+		_, target, err = getDefaultURLs()
+		if err != nil {
+			return err
 		}
+	default:
+		base = args[0]
+		target = args[1]
 	}
 
 	return eventLoop(
-		startDBDiffCmd(dbURL, deleteDatabases),
+		startDBDiffCmd(base, target, deleteDatabases),
 		setupSignals(),
 		eventSubscription,
 		stereoscope.Cleanup,
@@ -124,27 +127,25 @@ func runDBDiffCmd(cmd *cobra.Command, args []string) error {
 	)
 }
 
-func getDefaultURL() (defaultURL []*url.URL, err error) {
+func getDefaultURLs() (baseURL string, targetURL string, err error) {
 	dbCurator, err := db.NewCurator(appConfig.DB.ToCuratorConfig())
 	if err != nil {
-		return nil, err
+		return "", "", err
 	}
 
 	listing, err := dbCurator.ListingFromURL()
 	if err != nil {
-		return nil, err
+		return "", "", err
 	}
 
 	supportedSchema := dbCurator.SupportedSchema()
 	available, exists := listing.Available[supportedSchema]
 	if len(available) < 2 || !exists {
-		return nil, stderrPrintLnf("Not enough databases available for the current schema to diff (%d)", supportedSchema)
+		return "", "", stderrPrintLnf("Not enough databases available for the current schema to diff (%d)", supportedSchema)
 	}
 
-	recent := available[:2]
-	for _, entry := range recent {
-		defaultURL = append([]*url.URL{entry.URL}, defaultURL...)
-	}
+	targetURL = available[0].URL.String()
+	baseURL = available[1].URL.String()
 
-	return defaultURL, nil
+	return baseURL, targetURL, nil
 }
diff --git a/grype/differ/differ.go b/grype/differ/differ.go
index d3e568291e4..b80e18e6acf 100644
--- a/grype/differ/differ.go
+++ b/grype/differ/differ.go
@@ -49,40 +49,51 @@ func NewDiffer(config db.Config) (*Differ, error) {
 	}, nil
 }
 
-func (d *Differ) DownloadDatabases(baseURL, targetURL *url.URL) error {
-	listing, err := d.baseCurator.ListingFromURL()
-	if err != nil {
-		return err
-	}
+func (d *Differ) SetBaseDB(base string) error {
+	return d.setOrDownload(&d.baseCurator, base)
+}
 
-	listings := listing.Available
-	dbs := listings[v5.SchemaVersion]
+func (d *Differ) SetTargetDB(target string) error {
+	return d.setOrDownload(&d.targetCurator, target)
+}
 
-	var baseListing *db.ListingEntry
-	var targetListing *db.ListingEntry
+func (d *Differ) setOrDownload(curator *db.Curator, filenameOrURL string) error {
+	u, err := url.ParseRequestURI(filenameOrURL)
 
-	for _, db := range dbs {
-		database := db
-		if *db.URL == *baseURL {
-			baseListing = &database
+	if err != nil || u.Scheme == "" {
+		*curator, err = db.NewCurator(db.Config{
+			DBRootDir: filenameOrURL,
+		})
+		if err != nil {
+			return err
 		}
-		if *db.URL == *targetURL {
-			targetListing = &database
+	} else {
+		listings, err := d.baseCurator.ListingFromURL()
+		if err != nil {
+			return err
 		}
-	}
 
-	if baseListing == nil {
-		return fmt.Errorf("unable to find listing for base url: %s", baseURL.String())
-	} else if targetListing == nil {
-		return fmt.Errorf("unable to find listing for target url: %s", targetURL.String())
-	}
+		available := listings.Available
+		dbs := available[v5.SchemaVersion]
 
-	if err := download(&d.baseCurator, baseListing); err != nil {
-		return fmt.Errorf("unable to update base vulnerability database: %+v", err)
-	}
-	if err := download(&d.targetCurator, targetListing); err != nil {
-		return fmt.Errorf("unable to update target vulnerability database: %+v", err)
+		var listing *db.ListingEntry
+
+		for _, d := range dbs {
+			database := d
+			if *d.URL == *u {
+				listing = &database
+			}
+		}
+
+		if listing == nil {
+			return fmt.Errorf("unable to find listing for url: %s", filenameOrURL)
+		}
+
+		if err := download(curator, listing); err != nil {
+			return fmt.Errorf("unable to download vulnerability database: %+v", err)
+		}
 	}
+
 	return nil
 }
 
diff --git a/grype/differ/differ_test.go b/grype/differ/differ_test.go
index 190157087b5..7aee002caaa 100644
--- a/grype/differ/differ_test.go
+++ b/grype/differ/differ_test.go
@@ -3,6 +3,7 @@ package differ
 import (
 	"bytes"
 	"flag"
+	"strconv"
 	"testing"
 
 	"github.com/sergi/go-diff/diffmatchpatch"
@@ -11,6 +12,7 @@ import (
 	"github.com/anchore/go-testutils"
 	"github.com/anchore/grype/grype/db"
 	v5 "github.com/anchore/grype/grype/db/v5"
+	"github.com/anchore/grype/grype/vulnerability"
 )
 
 var update = flag.Bool("update", false, "update the *.golden files for diff presenter")
@@ -27,6 +29,25 @@ func TestNewDiffer(t *testing.T) {
 	require.NotNil(t, differ.baseCurator)
 }
 
+func Test_DifferDirectory(t *testing.T) {
+	d, err := NewDiffer(db.Config{
+		DBRootDir: "root-dir",
+	})
+	require.NoError(t, err)
+
+	err = d.SetBaseDB("test-fixtures/dbs/base")
+	require.NoError(t, err)
+
+	baseStatus := d.baseCurator.Status()
+	require.Equal(t, "test-fixtures/dbs/base/"+strconv.Itoa(vulnerability.SchemaVersion), baseStatus.Location)
+
+	err = d.SetTargetDB("test-fixtures/dbs/target")
+	require.NoError(t, err)
+
+	targetStatus := d.targetCurator.Status()
+	require.Equal(t, "test-fixtures/dbs/target/"+strconv.Itoa(vulnerability.SchemaVersion), targetStatus.Location)
+}
+
 func TestPresent_Json(t *testing.T) {
 	//GIVEN
 	diffs := []v5.Diff{
diff --git a/grype/differ/test-fixtures/dbs/base/5/metadata.json b/grype/differ/test-fixtures/dbs/base/5/metadata.json
new file mode 100644
index 00000000000..979e3bdce16
--- /dev/null
+++ b/grype/differ/test-fixtures/dbs/base/5/metadata.json
@@ -0,0 +1,5 @@
+{
+ "built": "2022-12-18T08:18:18Z",
+ "version": 5,
+ "checksum": "sha256:9d979f7320c575e7ac41c4384e9f55d578cdddd701822563cabc6b913fde7b80"
+}
\ No newline at end of file
diff --git a/grype/differ/test-fixtures/dbs/base/5/vulnerability.db b/grype/differ/test-fixtures/dbs/base/5/vulnerability.db
new file mode 100644
index 00000000000..946abdcb17a
--- /dev/null
+++ b/grype/differ/test-fixtures/dbs/base/5/vulnerability.db
@@ -0,0 +1 @@
+an older vulnerability db
\ No newline at end of file
diff --git a/grype/differ/test-fixtures/dbs/target/5/metadata.json b/grype/differ/test-fixtures/dbs/target/5/metadata.json
new file mode 100644
index 00000000000..90c5b117ebc
--- /dev/null
+++ b/grype/differ/test-fixtures/dbs/target/5/metadata.json
@@ -0,0 +1,5 @@
+{
+ "built": "2022-12-18T08:18:18Z",
+ "version": 5,
+ "checksum": "sha256:da2141ae7415abe5cf5390faeed60e164c5a919370ee823c8cc3ad9f4698f56e"
+}
\ No newline at end of file
diff --git a/grype/differ/test-fixtures/dbs/target/5/vulnerability.db b/grype/differ/test-fixtures/dbs/target/5/vulnerability.db
new file mode 100644
index 00000000000..2e85d70e599
--- /dev/null
+++ b/grype/differ/test-fixtures/dbs/target/5/vulnerability.db
@@ -0,0 +1 @@
+a vulnerability db
\ No newline at end of file