Tatyana Andrianova's two-year doping ban has been overturned by the Court of Arbitration for Sport (CAS).
Andrianova was sanctioned by the All-Russia Athletic Federation (ARAF) in 2015 following re-analysis of a sample taken 10 years previously at the 2005 World Championships in Helsinki, which identified the presence of a banned steroid stanozolol.
As a result of the suspension, Andrianova's results between August 2005 and August 2007 - which included her bronze in the 800 metres in Helsinki - were annulled.
The IAAF believed a ban could be enforced following a 2015 ruling that increased a statute of limitations from eight years to 10, but Andrianova submitted an appeal, which was upheld on Thursday.
A CAS statement read: "The Sole Arbitrator found that ARAF erroneously opened disciplinary proceedings against the Athlete in August 2015 - more than eight years after her sample collection - and that for this reason the appeal had to be upheld and the ARAF ADC decision annulled.
"As the eight-year statute of limitations had expired prior to 1 January 2015, the 10-year statute of limitations provided under the new 2015 ADR cannot apply."