diff --git a/deps/mbedtls/bignum.c b/deps/mbedtls/bignum.c
index aa98e21047..9913c33499 100644
--- a/deps/mbedtls/bignum.c
+++ b/deps/mbedtls/bignum.c
@@ -1101,7 +1101,7 @@ __attribute__ ((noinline))
 #endif
 void mpi_mul_hlp( size_t i, mbedtls_mpi_uint *s, mbedtls_mpi_uint *d, mbedtls_mpi_uint b )
 {
-    mbedtls_mpi_uint c = 0;
+    mbedtls_mpi_uint c = 0, t = 0;
 
 #if defined(MULADDC_HUIT)
     for( ; i >= 8; i -= 8 )