In FreeBSD 12.2-STABLE before r365730, 11.4-STABLE before r365738, 12.1-RELEASE before p10, 11.4-RELEASE before p4, and 11.3-RELEASE before p14, a programming error in the ure(4) device driver caused some Realtek USB Ethernet interfaces to incorrectly report packets with more than 2048 bytes in a single USB transfer as having a length of only 2048 bytes. An adversary can exploit this to cause the driver to misinterpret part of the payload of a large packet as a separate packet, and thereby inject packets across security boundaries such as VLANs.