Reinhardt
Another victim of Sombra’s chief claim-to-fame, being hacked would also put Reinhardt in a pretty tough spot. He would not only lose his ability to don the energy shield, but would also be unable to charge or launch a fireball. This eliminates his greatest defense and any chance he has to close the distance or pick off squishy enemies from afar.
Suffice to say, a hacked Reinhardt is suddenly a shieldless, melee-only Reinhardt that could be in big trouble. His only saving grace is that Sombra has to get pretty close to activate a hack, so if she doesn’t immediately teleport back to safety or invisibly run away, Reinhardt has a chance to take out the Sombra who killed his shield.
Torbjorn
Sombra doesn’t counter the lovable dwarf himself as much as his automated baby, the turret. A well-timed hack on the turret will completely disable it for a short time. This opens the window to destroy it completely using her 60-bullet clip machine pistol. However, she still has to be careful around the turret. Her hacking requires holding the input, and with only 200 health and no armor, shields, or way to self-heal, the turret could chew her up quickly if caution isn’t taken.