diff --git a/library/rsa.c b/library/rsa.c
index 1f907b7..efdd055 100644
--- a/library/rsa.c
+++ b/library/rsa.c
@@ -1086,10 +1086,16 @@
      * temporary buffer and check it before returning it.
      */
     sig_try = mbedtls_calloc( 1, ctx->len );
-    verif   = mbedtls_calloc( 1, ctx->len );
-    if( sig_try == NULL || verif == NULL )
+    if( sig_try == NULL )
         return( MBEDTLS_ERR_MPI_ALLOC_FAILED );
 
+    verif   = mbedtls_calloc( 1, ctx->len );
+    if( verif == NULL )
+    {
+        mbedtls_free( sig_try );
+        return( MBEDTLS_ERR_MPI_ALLOC_FAILED );
+    }
+
     MBEDTLS_MPI_CHK( mbedtls_rsa_private( ctx, f_rng, p_rng, sig, sig_try ) );
     MBEDTLS_MPI_CHK( mbedtls_rsa_public( ctx, sig_try, verif ) );