CVE-2026-75084: Out-of-bounds Write

The CC1200 sub-GHz IEEE 802.15.4 driver takes the PHY packet length from the first byte of the radio's RX FIFO in getpacketlength and validates it in verifyrxfifovalidity drivers/ieee802154/ieee802154cc1200.c. That validation only enforced a lower bound pktlen data and then calls netbufadd with t...