CVE-2026-68368

Technical Description

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 str

Remediation

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

References