According to a report, Die Roten Bullen sealed their place in Europe's elite club competition after winning the Austrian Bundesliga, while Die Bullen qualified as runners-up to German Bundesliga champions Bayern Munich.
Due to the connection between them and Red Bull, who owns the two teams, the participation of the Saxony outfit was cast into doubt over regulations pertaining to the integrity of the competition.
However, UEFA has cleared the pair for continental action following an extensive investigation.
"The Adjudicatory Chamber of the UEFA Club Financial Control Body (CFCB) has decided to accept the admission of both FC Salzburg and RB Leipzig to the UEFA Champions League 2017/18, having found that Article 5 (Integrity of the competition) of the competition regulations is not breached," read a statement from UEFA.
"Following a thorough investigation, and further to several important governance and structural changes made by the clubs (regarding corporate matters, financing, personnel, sponsorship arrangements, etc.), the CFCB deemed that no individual or legal entity had anymore a decisive influence over more than one club participating in a UEFA club competition.
"This decision may be appealed to the Court of Arbitration for Sport within 10 days, in accordance with Article 34(2) of the Procedural rules governing the UEFA Club Financial Control Body - Edition 2015, as well as Articles 62 and 63 of the UEFA Statutes.
"The CFCB will continue to monitor both clubs to ensure that integrity rules are respected going forward."