The incident occurred during the first session of cricket with England batting, and Sreesanth was initially spoken to by South African umpire Ian Howell.
He pleaded guilty to a charge of breaching the ICC Code of Conduct, specifically clause 2.4, which relates to "inappropriate and deliberate physical contact between players in the course of play."
"Cricket is a non-contact sport and any deviation from that fact is completely unacceptable, a point I made to Sreesanth in handing down my verdict," said ICC match referee Ranjan Madugalle, who convened the hearing after play concluded on the fourth day of the second Test.
"I have no problem with players being combative on the field but there is a line they cannot cross and Sreesanth crossed that line when he barged past Michael Vaughan, a collision he had every opportunity to avoid.
"I am pleased that Sreesanth accepted he was in the wrong by pleading guilty and that he apologised for his actions and I hope he learns from his mistake here," Madugalle said.
Level Two breaches like that committed by Sreesanth carry a minimum penalty of a fine of 50 per cent of a player's match fee, and/or a one Test match, or two One-Day International ban.
With one day left to play in the Test, India were left needing a further 63 runs to achieve only their fifth win in 47 Tests in England. The third and final Test in the series is at The Oval in London.