CVE-2026-68368

In the Linux kernel, the following vulnerability has been resolved:

usb: gadget: f_ncm: validate datagram bounds in ncm_unwrap_ntb()

When unpacking host-supplied NTBs, ncm_unwrap_ntb() checks datagram length

against frame_max but does not verify that the datagram fits within the

declared block length. Additionally, when decoding multiple NTBs from a

single socket buffer, subsequent block lengths are not checked against the

actual remaining buffer data.

With these checks missing, a malicious USB host can specify datagram

offsets and lengths that point beyond the block, or supply secondary NTB

headers declaring lengths larger than the buffer. skb_put_data() then

copies adjacent kernel memory from skb_shared_info into the network skb.

Fix this by verifying that sufficient buffer space remains for the NTB

header before parsing, handling zero-length block declarations, ensuring

that block lengths never exceed the remaining buffer space, and verifying

that each datagram payload stays strictly within the block boundary.