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CVE-2026-68368

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

Published
Last modified
published
Not listed in CISA KEV
Fix
Fixed in 4.10, 4.15, 4.20, 5.5, 5.9
None on Exploit-DB, Metasploit or GitHub

Summary

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.

Timeline

  1. CVE published
  2. Record last updated

Affected versions

  • Linux Linux

    From 4.9.235 · fixed in 4.10; From 4.14.196 · fixed in 4.15; From 4.19.143 · fixed in 4.20; From 5.4.62 · fixed in 5.5; From 5.8.6 · fixed in 5.9; From 4.14.328 · fixed in 4.15; From 4.19.297 · fixed in 4.20; From 5.4.259 · fixed in 5.5

  • Linux Linux

    5.9

References 8

git.kernel.org