Alinghi sailor Simon Daubney tested positive to cocaine, and not cannabis as earlier reported, during this year's America's Cup match with Team New Zealand in Valencia.
Daubney believed a drink spiked by "a small unruly element" who opposed his move from Team NZ to Alinghi seven years ago was to blame.
An America's Cup jury accepted his contention that he had not knowingly taken a banned substance.
It said the International Sailing Federation had jurisdiction in respect of any penalty.
Daubney, one of six New Zealanders in Alinghi's crew during their successful defence against Team NZ in June and July in Spain, was last week reported to have failed a doping test for cannabis.
The test was done on a urine sample taken on June 23, the day of the opening race of a match that Alinghi eventually won 5-2.
Daubney appeared before the cup jury at a hearing in London last week over the failed test.
The jury's decision, issued at the weekend, said analysis of the sample revealed the presence of two metabolites of cocaine.
It said Daubney believed he had been the victim of a spiked drink which had been bought for him in the week before the sample was taken.
The genoa trimmer blamed people who had opposed his and five other New Zealand sailors' decision to leave Team NZ in 2000.
Daubney told the jury he had been subjected to considerable personal harassment at times over that decision.
He gave further evidence that he received in his mailbox at the Alinghi base on the day after the test a note stating: "I heard you were tested. How did you get on? Ha Ha."
He discarded the note, thinking it was a practical joke.
Among five witnesses Daubney called were Alinghi skipper Brad Butterworth and fellow New Zealand sailor Russell Coutts, the latter giving evidence by telephone.
The witnesses testified that, in their experience, Daubney had never taken any banned drug and they could not believe he would have knowingly taken cocaine.
The positive result was the first in the cup's 156-year history, and America's Cup Management chief executive Michel Hodara said it was the only one of the 2007 competition.
Christchurch-born Daubney, 48, has been in the winning cup crew for the past four regattas, the first two with Team NZ in 1995 and 2000.
Along with Coutts, Butterworth and three other compatriots, he jumped ship and joined Alinghi, and had been part of the Swiss syndicate's two successful campaigns since.
Aspects of his case - the A sample test wasn't completed until July 9, a week after racing finished, and the result initially came to light only when revealed by media - has led to speculation of a cover-up.
After the hearing, Daubney said he was relieved the jury had found there was no fault or negligence on his part.
However, he had resigned from Alinghi while the matter was resolved, but he hoped to rejoin the syndicate when his name was cleared.
Under cup rules, Alinghi will not lose the America's Cup because crew members are individually responsible for doping.
Daubney does, however, risk a two-year suspension, which would rule him out of the next cup regatta in Valencia in 2009.