Please do not open a public issue for security problems.

Report them privately through GitHub Security Advisories ("Report a vulnerability"). You should get an acknowledgement within a week.

sextante is a hardware driver that talks to a local I2C bus; it opens no network sockets and parses no untrusted input by itself. Reports are nonetheless welcome for anything that could make a host application misbehave — e.g. unbounded resource usage in the sampling threads, or unsafe handling of values read from the bus.