The 29-year-old Finland international was tested after CSKA’s 2-2 draw with Bayer Leverkusen in the Champions League on 14 September. He scored the Russian club’s equaliser.
His ban runs until 6 October 2018.
A Uefa statement said: “The analysis of the A sample revealed the presence of cocaine and its metabolites.”
He is best known for his time in Dynamo Kyiv, with whom he became captain, winning the Ukrainian Premier League title in 2009, and playing in the Champions and Europa Leagues.
He also plays regularly for the Finland national football team.
He made his international debut for Finland in June 2007, at the age of 20.
He started his senior club career with Jaro. He then went on to play for Udinese, Siena (on loan) and Rubin Kazan.
He moved to Finland with his family at the age of three when his father, former FC Dynamo Moscow and FC Spartak Moscow player Alexei Eremenko Sr., came to play in Finland with FF Jaro.
He was granted Finnish citizenship in 2003, but still holds a Russian passport as well, Eremenko is the younger brother of Alexei Eremenko Jr. His father took over as manager in Jaro in August 2009.
