All solar panel datasheet have temp coefficient, eg for one random ecoflow solar panel:
Temperature Coefficient Specifications
TKPower -(0.39±0.02)%/k
TKVoltage -(0.33±0.03)%/k
TKCurrent +(0.06±0.015)%/k
STC ("standard testing conditions" for solar panels) is 25C so if it's freezing 0C you have 25 multiplied by 0.33 Volt = 8.25 Volt more than STC in open circuit situation.
Unfortunately inverter manufacturers seldom document how many Volt will destroy the MPPT and up to how many Volt the MPPT will safely turn off by itself before breaking.
Not to mention a fail-safe MPPT would/should just crowbar the input if there's any potential for overvoltage.
Solar panels are current sources that waste their power into a long string of silicon PIN diodes that eventually reach their forward voltage and begin to eat up all that juicy current. You can just take the current and keep the voltage as low as you want, just make sure to take all the current or it's voltage will rise to let the diodes take the current you aren't using.