Here is a brief list of your travelling options according to security status:

Players with -2.0 or worse will be attacked in 1.0 systems
Players with -2.5 or worse will be attacked in 0.9 systems
Players with -3.0 or worse will be attacked in 0.8 systems
Players with -3.5 or worse will be attacked in 0.7 systems
Players with -4.0 or worse will be attacked in 0.6 systems
Players with -4.5 or worse will be attacked in 0.5 systems

Once your security status reaches -5 you are considered an outlaw and can be attacked by players anywhere without CONCORD intervention. Be really careful about CONCORD Assembly Sovereignty! - CONCORD marks the ship as an outlaw and you are not able to jump out of the system or move in general: you will be shot down

Good luck lmao