diff --git a/library/ssl_tls.c b/library/ssl_tls.c

index 2e6469de8..2357bdf3f 100644

--- a/library/ssl_tls.c

+++ b/library/ssl_tls.c

@@ -3334,7 +3334,7 @@ static void ssl_calc_finished_tls_sha384(

 {

     int len = 12;

     const char *sender;

-    unsigned char padbuf[48];

+    unsigned char padbuf[64];

 #if defined(MBEDTLS_USE_PSA_CRYPTO)

     size_t hash_size;

     psa_hash_operation_t sha384_psa = PSA_HASH_OPERATION_INIT;