VulnerabilityPublished 10 Aug 2026Updated 6 Nov 2026

CVE-2026-68368: Linux kernel · usb: gadget: f_ncm: validate datagram bounds in ncm_unwrap_ntb()

Affects Linux kernelSource CVE Database V5

Compare

Not known to be exploited · fixed in fff1059d139ef798bab917990524faaf25854ca8 : update Linux kernel when convenient.

Data as of 6 Nov 2026, 17:04 UTC

Severity

Unrated

Rated by Threat Radar · No CVSS score from NVD or the CNA

Thin evidence

One scorer or none

Exploitation: No evidence of active exploitation and no public proof of concept
Automatable: Attackers cannot reliably automate steps 1–4 of the kill chain
Technical impact: Limited control over the software or limited information exposure

CISA SSVC assessment, 2026-11-06.

Patch

Available – fixed in fff1059d139ef798bab917990524faaf25854ca8, f87ed889f0f7417b8938c98d8833f559b755373c, e07751d0527ccc2a1c32eb0b0b7da3b4b9b5381f +10

Exploitation evidence

Disclosed: evidence found.
CVE published 10 Aug 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 6 Nov 2026.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponized: A Metasploit exploit module or Exploit-DB entry exists (Metasploit scanner modules do not count), or CISA SSVC or the CVSS exploit maturity reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

What to do

Upgrade to a fixed release listed under Affected software.

Affected software

Product	Affected	Fixed in
LinuxLinux	Affected >=4.9.235 <4.10 >=4.14.196 <4.15 >=4.19.143 <4.20 >=5.4.62 <5.5 >=5.8.6 <5.9 >=4.14.328 <4.15 >=4.19.297 <4.20 >=5.4.259 <5.5	Fixed in fff1059d139ef798bab917990524faaf25854ca8 f87ed889f0f7417b8938c98d8833f559b755373c e07751d0527ccc2a1c32eb0b0b7da3b4b9b5381f 41fd5f2fb0027d3773ae949e3247c2e0a2a7fe5c 40c706a0224bde194667e3378c689b542fec4b44 35d15bbaec0557330e774ec31412ef508de6e0e0 6b2be489eaa6293e60549005d91f15ceb150510f 5.9 5.5 4.20 4.15 4.10 1febec7e47cdcd01f43fb0211094e3010474666e
LinuxLinux	Affected =5.9	Fixed in–

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 strictly within the block boundary.

References

Community reviews

Loading reviews…