Prioritisation of bugs

We need an agreed definition or understanding on the priority of the bugs we find during testing. The following is my suggested approach, but I am open to feedback

 

RatingActionUrgency

Highest

Must be fixedWithin 24 hours (if at all possible), as it delays other testing
HighMust be fixedWithin one week (if at all possible), but before go-live
MediumMust be fixedShould be fixed before go live, but can be later so long as fixed in the project. Could allow for fixing in the next phase of the project.
LowShould be fixedShould be fixed in the project, but can be left for BAU to address later
LowestNo action requiredWe can live with it as is, indefinitely