diff --git a/library/x509write_csr.c b/library/x509write_csr.c
index f2950ad..777a632 100644
--- a/library/x509write_csr.c
+++ b/library/x509write_csr.c
@@ -142,7 +142,7 @@
     size_t len = 0;
     mbedtls_pk_type_t pk_alg;
 #if defined(MBEDTLS_USE_PSA_CRYPTO)
-    psa_hash_operation_t hash_operation;
+    psa_hash_operation_t hash_operation = PSA_HASH_OPERATION_INIT;
     size_t hash_len;
     psa_algorithm_t hash_alg = mbedtls_psa_translate_md( ctx->md_alg );
 #endif /* MBEDTLS_USE_PSA_CRYPTO */