Bug priority is nothing but an indication of how important or urgent to get the bug fix.
Typically divided into five levels: P1 (highest), P2, P3, P4, P5 (lowest).
- P1: Need immediate fix ( tests blocking) within 24hrs
- P2: Need by next build (major functionality is not working)
- P3: It is ok to wait but fix before release
- P4/P5: It is not mandatory, it is ok to fix or not in the current release.
The bug filer would determine the priority and set while filing the bug. The thumb rule is to set the same priority as severity while filing the bugs. Example: P1/S1, P2/S2, P3/S3, P4/S4, P5/S5.
Note that anyone can change the bug priority and bug tools would allow that. Typically, changed after the conversations with stakeholders like release managers and product managers. Example: QA can file a bug, but Dev manager or product manager can change the priority.