Bug 2454838 (CVE-2026-23447)

Summary:	CVE-2026-23447 kernel: net: usb: cdc_ncm: add ndpoffset to NDP32 nframes bounds check
Product:	[Other] Security Response	Reporter:	OSIDB Bzimport <bzimport>
Component:	vulnerability	Assignee:	Product Security DevOps Team <prodsec-dev>
Status:	NEW ---	QA Contact:
Severity:	medium	Docs Contact:
Priority:	medium
Version:	unspecified	Keywords:	Security
Target Milestone:	---
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Hardware:	All
OS:	Linux
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Doc Text:	A flaw was found in the USB CDC NCM (Network Control Model) driver in the Linux kernel. This vulnerability, a bounds-check bug, occurs when processing NCM Datagram Pointer (NDP32) frames. It fails to correctly account for the `ndpoffset`, which can lead to out-of-bounds reads. This could result in information disclosure or system instability.	Story Points:	---
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oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---	Target Upstream Version:
Embargoed:

Description OSIDB Bzimport 2026-04-03 16:03:32 UTC

In the Linux kernel, the following vulnerability has been resolved:

net: usb: cdc_ncm: add ndpoffset to NDP32 nframes bounds check

The same bounds-check bug fixed for NDP16 in the previous patch also
exists in cdc_ncm_rx_verify_ndp32(). The DPE array size is validated
against the total skb length without accounting for ndpoffset, allowing
out-of-bounds reads when the NDP32 is placed near the end of the NTB.

Add ndpoffset to the nframes bounds check and use struct_size_t() to
express the NDP-plus-DPE-array size more clearly.

Compile-tested only.

Comment 1 Jon Moroney 2026-04-03 18:15:59 UTC

Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2026040315-CVE-2026-23447-dd25@gregkh/T