Cut and paste this URL to share the unmodified register and value:
https://regviz.com/r/stm32/stm32n6/STM32N645/EXTI/EXTI_LOCKR#0x0
GLOCK=B_0x0
EXTI lock register
Global security privilege EXTI_SECCFGRx/PRIVCFGRx
0 (B_0x0): Security, privilege open can be modified.
1 (B_0x1): Security, privilege locked can no longer be modified.
https://github.com/modm-io/cmsis-svd-stm32