How to convert a hex string to an image vector

Question

I am making an API that reads an image as a hex string. I need to convert the hex string to an image vector like what you would get from: img = cv2.imread('abc.jpg')

I know I can do this by writing hex string to file and read as an image:

import cv2
image_name = 'Test_image.jpg'

with open(image_name, 'wb') as outfile:
                outfile.write(hex_string)

img = cv2.imread(image_name)

But my question is how to end up with "img" directly from "hex_string" without needing to write/read from file.