Linux kernel usb cdc_ncm: OOB read due to missing ndpoffset in NDP16 check
CVE-2026-23448 Published on April 3, 2026
net: usb: cdc_ncm: add ndpoffset to NDP16 nframes bounds check
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.
Products Associated with CVE-2026-23448
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Affected Versions
Linux:- Version ff06ab13a4ccae4acb44a2d4e3ece367b616ab50 and below f1c7701d3ac91b62d672c13690cf295821f0d5c3 is affected.
- Version ff06ab13a4ccae4acb44a2d4e3ece367b616ab50 and below 789204f980730258c983102c027c375238009c80 is affected.
- Version ff06ab13a4ccae4acb44a2d4e3ece367b616ab50 and below 403f94ddcb36c552fbef51dea735b131e3dcde8b is affected.
- Version ff06ab13a4ccae4acb44a2d4e3ece367b616ab50 and below dce9dda0e3707e887977db44407989e9ead26611 is affected.
- Version ff06ab13a4ccae4acb44a2d4e3ece367b616ab50 and below 2aa8a4fa8d5b7d0e1ebcec100e1a4d80a1f4b21a is affected.
- Version 3.8 is affected.
- Before 3.8 is unaffected.
- Version 6.6.130, <= 6.6.* is unaffected.
- Version 6.12.78, <= 6.12.* is unaffected.
- Version 6.18.20, <= 6.18.* is unaffected.
- Version 6.19.10, <= 6.19.* is unaffected.
- Version 7.0-rc5, <= * is unaffected.