VulnerabilityPublished 3 Apr 2026Updated 5 Nov 2026

CVE-2026-23448: Linux kernel · net: usb: cdc_ncm: add ndpoffset to NDP16 nframes bounds check

Affects Linux kernelSource CVE Database V5

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Not known to be exploited · fixed in f1c7701d3ac91b62d672c13690cf295821f0d5c3 : update Linux kernel when convenient.

Data as of 5 Nov 2026, 22:04 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, 2026-11-05.

Patch

Available – fixed in f1c7701d3ac91b62d672c13690cf295821f0d5c3, dce9dda0e3707e887977db44407989e9ead26611, 789204f980730258c983102c027c375238009c80 +3

Exploitation evidence

Disclosed: evidence found.
CVE published 3 Apr 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 5 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 ≥ ff06ab13a4ccae4acb44a2d4e3ece367b616ab50, < f1c7701d3ac91b62d672c13690cf295821f0d5c3	Fixed in f1c7701d3ac91b62d672c13690cf295821f0d5c3
LinuxLinux	Affected ≥ ff06ab13a4ccae4acb44a2d4e3ece367b616ab50, < dce9dda0e3707e887977db44407989e9ead26611	Fixed in dce9dda0e3707e887977db44407989e9ead26611
LinuxLinux	Affected ≥ ff06ab13a4ccae4acb44a2d4e3ece367b616ab50, < 789204f980730258c983102c027c375238009c80	Fixed in 789204f980730258c983102c027c375238009c80
LinuxLinux	Affected ≥ ff06ab13a4ccae4acb44a2d4e3ece367b616ab50, < 403f94ddcb36c552fbef51dea735b131e3dcde8b	Fixed in 403f94ddcb36c552fbef51dea735b131e3dcde8b
LinuxLinux	Affected ≥ ff06ab13a4ccae4acb44a2d4e3ece367b616ab50, < 63c35b8fce77a7892e8fa06c540d4943145506eb	Fixed in 63c35b8fce77a7892e8fa06c540d4943145506eb
LinuxLinux	Affected ≥ ff06ab13a4ccae4acb44a2d4e3ece367b616ab50, < 2aa8a4fa8d5b7d0e1ebcec100e1a4d80a1f4b21a	Fixed in 2aa8a4fa8d5b7d0e1ebcec100e1a4d80a1f4b21a

Description

In the Linux kernel, the following vulnerability has been resolved: net: usb: cdc_ncm: add ndpoffset to NDP16 nframes bounds check cdc_ncm_rx_verify_ndp16() validates that the NDP header and its DPE entries fit within the skb. The first check correctly accounts for ndpoffset: if ((ndpoffset + sizeof(struct usb_cdc_ncm_ndp16)) > skb_in->len) but the second check omits it: if ((sizeof(struct usb_cdc_ncm_ndp16) + ret * (sizeof(struct usb_cdc_ncm_dpe16))) > skb_in->len) This validates the DPE array size against the total skb length as if the NDP were at offset 0, rather than at ndpoffset. When the NDP is placed near the end of the NTB (large wNdpIndex), the DPE entries can extend past the skb data buffer even though the check passes. cdc_ncm_rx_fixup() then reads out-of-bounds memory when iterating the DPE array. Add ndpoffset to the nframes bounds check and use struct_size_t() to express the NDP-plus-DPE-array size more clearly.

References

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