The glamour model's accident occurred when two wild stallions, who were killed instantly, collided with Penna's Toyota jeep, which was written off.
Speaking to The Mirror, Price - who is thought to have suffered cuts to her hands and whiplash - reflected: "It was absolutely terrifying.
"It all happened in a flash and I have absolutely no idea how I wasn't badly injured. I feel so lucky, but more than anything I'm just distraught about the horses. It was so upsetting."
Meanwhile, a source claimed: "Quite frankly, it beggars belief that Katie and Leo survived at all. And Katie knows just how close she came to dying.
"The two animals ploughed into their vehicle, with one flying through the windscreen, backside-first, hitting both Katie and Leo simultaneously."
The insider added: "Luckily, Leandro reacted lightning-quick, braked hard and swerved violently the moment he saw the horses. Although it wasn't enough to save the horses, undoubtedly his reactions saved the pair's lives, plus those of the three passengers in the back.
"But Kate was far more concerned about the death of the stallions than she was her own injuries. She is badly shaken up and she was in pieces all of last night."
A spokesperson for Price confirmed the incident, saying that she and Penna were "'OK, though understandably shaken".
Price has said that she "can't thank" Sir Elton John enough for helping her meet Penna. It was recently claimed that she plans to adopt a child from his native Argentina.
