The court thereby granted an appeal by prosecutors from the North Caucasus republic, saying that procedures had been violated when the case was first considered.
"The verdict has been quashed, as violations of the Criminal Procedural Code were made. Only that can serve as grounds to annul a verdict brought by a jury," a court source said, without specifying the supposed violations.
During the hearings, the defense insisted that the prosecutors' appeal should not be granted, as they said the case had been lawfully considered by Daghestan's Supreme Court.
Salikhov, who was on the federal and international wanted lists and hid in Chechnya and outside Russia, was detained in Azerbaijan in November 2004.
Jurors have acquitted him twice on terrorism charges.
Daghestan's Supreme Court acquitted Salikhov in February 2006 on terrorism charges, but sentenced him to over four years in prison for participation in an illegal armed unit and using forged documents.
In June 2006, Russia's Supreme Court overturned the verdict, and in November 2006 Daghestan's Supreme Court acquitted Salikhov of all charges.
Seven other suspects in the Buinaksk terrorist attack earlier received various sentences, and two of them, including Salikhov's younger brother, were sentenced to life in prison.
