ipaccess: fix buffer overread in ipacc_parse_supp_flags()
The loop used OSMO_MAX(e->len, 4), which iterates at least 4 times even when the IE is shorter than 4 bytes, causing a buffer overread. Replace with OSMO_MIN(e->len, sizeof(u32)) to cap the iteration both at the actual IE length and at the uint32_t accumulator size.
