diff --git a/tests/drivers/uart/uart_pm/src/main.c b/tests/drivers/uart/uart_pm/src/main.c
index 07e75ec8dd6..e28d55efb33 100644
--- a/tests/drivers/uart/uart_pm/src/main.c
+++ b/tests/drivers/uart/uart_pm/src/main.c
@@ -66,7 +66,7 @@ static void async_callback(const struct device *dev, struct uart_event *evt, voi
 static bool async_verify(const struct device *dev, bool active)
 {
 	char txbuf[] = "test";
-	uint8_t rxbuf[32];
+	uint8_t rxbuf[32] = { 0 };
 	volatile bool tx_done = false;
 	int err;