If the camera has overvoltage protection based on voltage stabiliser, there is no risk. The stabiliser will just heat up wasting the extra volt.
If there is no protection, or a breaker, there is a hazzard of burning some crucial circuit in the camera. The voltage 4.3V is equal to voltage of three NiMH AA(A) cells in series.
If you are able to build some simple circuits, buy the plugs, 4.3V stabiliser or switching regulator and you are sure. You can also build voltage divider using two resistors or one potentiometer.
The chapest way is using the voltage divider. Choose the resistors parameters (Resistance, wattage limits) according to peak values displayed on camera and the charger. Peak current available from the charger shall be higher than then the peak current shown on the camera whatever solution you choose.
Another option is to build battery stack using battery cells,
M cells in series and
N cells in parallel.
Uc is single cell voltage, and
C is power capacity you want and
Cc is single cell power capacity (measured in mA.h).