diff --git a/drivers/media/cec/platform/stm32/stm32-cec.c b/drivers/media/cec/platform/stm32/stm32-cec.c
index 1ec0cece0a5b..8c2fc232202d 100644
--- a/drivers/media/cec/platform/stm32/stm32-cec.c
+++ b/drivers/media/cec/platform/stm32/stm32-cec.c
@@ -132,7 +132,8 @@ static void stm32_rx_done(struct stm32_cec *cec, u32 status)
 		u32 val;
 
 		regmap_read(cec->regmap, CEC_RXDR, &val);
-		cec->rx_msg.msg[cec->rx_msg.len++] = val & 0xFF;
+		if (cec->rx_msg.len < CEC_MAX_MSG_SIZE)
+			cec->rx_msg.msg[cec->rx_msg.len++] = val & 0xFF;
 	}
 
 	if (cec->irq_status & RXEND) {