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.
Executive briefing
The source record describes: 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. The practical risk depends on whether an affected product/version is present, reachable and configured in an exploitable way. Review the affected-product evidence and linked vendor advisories before assigning exposure status.
Evidence confidence: Limited Evidence-derived, not an exploitability verdict
Severity & attack characteristics
CVSS vector:
No CVSS vector is currently available in the source record.
Technical explanation & impact
The technical mechanism is not expanded beyond the source description unless a referenced advisory supplies additional evidence. Read the linked vendor/CERT advisories for root-cause detail.
Potential impact must be interpreted from the published CVSS impact metrics and the affected component. A CVSS impact score is not proof that a particular asset is exploitable.
Affected products and versions
NVD has not supplied machine-readable vulnerable CPE product/version entries for this CVE. This is an information gap, not proof that no products are affected. Check the vendor advisory references below.
Remediation & validation
- Identify exposure by comparing the affected product and version ranges with your asset inventory, SBOM and externally exposed services.
- Review the linked vendor security advisory or patch notes. Upgrade to a vendor-confirmed fixed release; do not infer a fixed version from the CVE description.
- Until patched, consider restricting network access or disabling the affected feature where operationally safe. These are temporary controls, not a substitute for a vendor fix.
- Validate the remediation with a version check and vulnerability rescan, then retain change evidence.
No fixed version is displayed unless it is explicitly established by a vendor advisory. Follow the vendor's release notes for exact product and branch applicability.
Vendor advisories, patches & exploit references
- https://git.kernel.org/stable/c/1febec7e47cdcd01f43fb0211094e3010474666e REFERENCE 416baaa9-dc9f-4396-8d5f-8c081fb06d67
- https://git.kernel.org/stable/c/35d15bbaec0557330e774ec31412ef508de6e0e0 VENDOR 416baaa9-dc9f-4396-8d5f-8c081fb06d67
- https://git.kernel.org/stable/c/40c706a0224bde194667e3378c689b542fec4b44 REFERENCE 416baaa9-dc9f-4396-8d5f-8c081fb06d67
- https://git.kernel.org/stable/c/41fd5f2fb0027d3773ae949e3247c2e0a2a7fe5c REFERENCE 416baaa9-dc9f-4396-8d5f-8c081fb06d67
- https://git.kernel.org/stable/c/6b2be489eaa6293e60549005d91f15ceb150510f REFERENCE 416baaa9-dc9f-4396-8d5f-8c081fb06d67
- https://git.kernel.org/stable/c/e07751d0527ccc2a1c32eb0b0b7da3b4b9b5381f REFERENCE 416baaa9-dc9f-4396-8d5f-8c081fb06d67
- https://git.kernel.org/stable/c/f87ed889f0f7417b8938c98d8833f559b755373c VENDOR 416baaa9-dc9f-4396-8d5f-8c081fb06d67
- https://git.kernel.org/stable/c/fff1059d139ef798bab917990524faaf25854ca8 REFERENCE 416baaa9-dc9f-4396-8d5f-8c081fb06d67
Information gaps & confidence notes
These gaps indicate missing source data. CVE Watch does not fill them with guessed product, exploit or patch details.
- NVD does not currently provide machine-readable vulnerable CPE product/version entries for this record.
- No CVSS vector is currently available in the source record.
- No CWE classification is currently available.
Last enrichment: 2026-11-07T16:31:49+00:00 · Source last modified: 2026-11-06T17:19:31.043