Oregon Revised Statutes Evidence and Witnesses § 40.350

(1) The credibility of a witness may be attacked or supported by evidence in the form of opinion or reputation, but:

(2) Specific instances of the conduct of a witness, for the purpose of attacking or supporting the credibility of the witness, other than conviction of crime as provided in ORS 40.355, may not be proved by extrinsic evidence. Further, such specific instances of conduct may not, even if probative of truthfulness or untruthfulness, be inquired into on cross-examination of the witness.