diff --git a/tests/suites/test_suite_x509write.data b/tests/suites/test_suite_x509write.data
index aa8b3cd..4cff30d 100644
--- a/tests/suites/test_suite_x509write.data
+++ b/tests/suites/test_suite_x509write.data
@@ -132,3 +132,6 @@
 
 X509 String to Names #6 (Escape at end)
 mbedtls_x509_string_to_names:"C=NL, O=Offspark\":"":MBEDTLS_ERR_X509_INVALID_NAME
+
+Check max serial length
+x509_set_serial_check:
diff --git a/tests/suites/test_suite_x509write.function b/tests/suites/test_suite_x509write.function
index 84da143..03ecdab 100644
--- a/tests/suites/test_suite_x509write.function
+++ b/tests/suites/test_suite_x509write.function
@@ -425,6 +425,24 @@
 }
 /* END_CASE */
 
+/* BEGIN_CASE depends_on:MBEDTLS_X509_CRT_WRITE_C */
+void x509_set_serial_check()
+{
+    mbedtls_x509write_cert ctx;
+    mbedtls_mpi serial_mpi;
+    uint8_t invalid_serial[MBEDTLS_X509_RFC5280_MAX_SERIAL_LEN + 1];
+
+    memset(invalid_serial, 0x01, sizeof(invalid_serial));
+
+    mbedtls_mpi_init(&serial_mpi);
+    TEST_EQUAL(mbedtls_mpi_read_binary(&serial_mpi, invalid_serial,
+                                       sizeof(invalid_serial)), 0);
+    TEST_EQUAL(mbedtls_x509write_crt_set_serial(&ctx, &serial_mpi),
+               MBEDTLS_ERR_X509_BAD_INPUT_DATA);
+    mbedtls_mpi_free(&serial_mpi);
+}
+/* END_CASE */
+
 /* BEGIN_CASE depends_on:MBEDTLS_X509_CREATE_C:MBEDTLS_X509_USE_C */
 void mbedtls_x509_string_to_names(char *name, char *parsed_name, int result
                                   )