What is the furthest a solar flare has reached off the suns surface?

Question: What is the furthest a solar flare has reached off the suns surface?
- Keywords:
  distance,
  solar flare,
  sun
Asked by 374expd44 to Jack on 7 Nov 2015. This question was also asked by LUKE_FOXY.
- Jack Carlyle answered on 7 Nov 2015:
  
  Solar flares are actually just a very bright flash, so they don’t really go anywhere. But they often come with big explosions – called coronal mass ejections – which can get all the way to the edge of the solar system! And that’s a really, REALLY long way.

Question: What is the furthest a solar flare has reached off the suns surface?