diff --git a/internal/crypto/passwap.go b/internal/crypto/passwap.go
index a5a293a449..479d5731e4 100644
--- a/internal/crypto/passwap.go
+++ b/internal/crypto/passwap.go
@@ -147,7 +147,7 @@ func (c *HasherConfig) buildHasher() (hasher passwap.Hasher, prefixes []string,
 
 func (c *HasherConfig) decodeParams(dst any) error {
 	decoder, err := mapstructure.NewDecoder(&mapstructure.DecoderConfig{
-		ErrorUnused: true,
+		ErrorUnused: false,
 		ErrorUnset:  true,
 		Result:      dst,
 	})
diff --git a/internal/crypto/passwap_test.go b/internal/crypto/passwap_test.go
index b557ca4a5c..0538ac631a 100644
--- a/internal/crypto/passwap_test.go
+++ b/internal/crypto/passwap_test.go
@@ -379,7 +379,10 @@ func TestHasherConfig_decodeParams(t *testing.T) {
 				"b": 2,
 				"c": 3,
 			},
-			wantErr: true,
+			want: dst{
+				A: 1,
+				B: 2,
+			},
 		},
 		{
 			name: "unset",