Commercial Fixed Wing
Flight Crew Air Transport Pilot (ATP)
Inflight Event / Encounter Wake Vortex Encounter
General Physical Injury / Incapacitation
Environment - Non Weather Related
In cruise with autopilot on; we encountered wake turbulence near BUF; one bump and that was all. Clear skies with no traffic in sight nor reported in the vicinity. When the Purser called to tell us he was submitting the cabin write ups; which was about 30 minutes after the bump; he also mentioned he was writing up that he may have tweaked his back during the turbulence. The Purser appeared to continue to do his duties without difficulty.
[Narrative 2 had no additonal information.]
Air carrier flight crew reported turbulence from a wake vortex encounter in cruise flight that resulted in a minor back injury to a flight attendant.