A vulnerability marked as problematic has been reported in FastNetMon Community Edition up to 1.2.9 . Affected by this vulnerability is the function append_dynamic_buffer/append_data_as_pointer/append_data_as_object_ptr/memcpy_from_ptr/memcpy_from_object_ptr of the file src/dynamic_binary_buffer.hpp . This manipulation causes off-by-one. This vulnerability is handled as CVE-2026-48689 . The attack can only be done within the local network. There is not any exploit available.