diff --git a/library/psa_crypto.c b/library/psa_crypto.c
index ca01e76..7188b12 100644
--- a/library/psa_crypto.c
+++ b/library/psa_crypto.c
@@ -1246,7 +1246,7 @@
     psa_key_slot_number_t *slot_number)
 {
     if (attributes->core.flags & MBEDTLS_PSA_KA_FLAG_HAS_SLOT_NUMBER) {
-        *slot_number = attributes->slot_number;
+        *slot_number = attributes->core.slot_number;
         return PSA_SUCCESS;
     } else {
         return PSA_ERROR_INVALID_ARGUMENT;