diff --git a/library/psa_crypto_rsa.c b/library/psa_crypto_rsa.c
index 508a68b..065e55a 100644
--- a/library/psa_crypto_rsa.c
+++ b/library/psa_crypto_rsa.c
@@ -328,9 +328,11 @@
     /* The Mbed TLS RSA module uses an unsigned int for hash length
      * parameters. Validate that it fits so that we don't risk an
      * overflow later. */
+#if SIZE_MAX > UINT_MAX
     if (hash_length > UINT_MAX) {
         return PSA_ERROR_INVALID_ARGUMENT;
     }
+#endif
 
     /* For signatures using a hash, the hash length must be correct. */
     if (alg != PSA_ALG_RSA_PKCS1V15_SIGN_RAW) {