---
id: CVE-2026-31622
title: |-
  In the Linux kernel, the following vulnerability has been resolved:

  NFC: digital: Bounds check NFC-A cascade depth in SDD response handler

  The NFC-A anti-collision cascade in digital_in_recv_sdd_res() appends 3
  or 4 bytes to target->nf…
summary: |-
  In the Linux kernel, the following vulnerability has been resolved:

  NFC: digital: Bounds check NFC-A cascade depth in SDD response handler

  The NFC-A anti-collision cascade in digital_in_recv_sdd_res() appends 3
  or 4 bytes to target->nf…
severity: high
cvss: 8.8
cvssVector: 'CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H'
cwe:
  - CWE-120
vendor: linux
product: linux_kernel
affected:
  - 'linux_kernel >= 3.13, < 6.6.136'
  - 'linux_kernel >= 6.7, < 6.12.83'
  - 'linux_kernel >= 6.13, < 6.18.24'
  - 'linux_kernel >= 6.19, < 6.19.14'
  - 'linux_kernel >= 7.0, < 7.0.1'
patched:
  - linux_kernel 7.0.1
published: '2026-04-24'
updated: '2026-10-15'
sourceUpdated: '2026-10-15T02:19:13.100'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-31622'
references:
  - url: 'https://git.kernel.org/stable/c/1bec5698b55aa2be5c3b983dba657c01d0fd3dbc'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/20663102c14566e900e1d2f679e30b7f1694f387'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/2819f34e08bdffb6f06a51c67948ec5737fb166a'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/46ce8be2ced389bccd84bcc04a12cf2f4d0c22d1'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/5a59bf70c38ee1eb4be03bab830bbc3a6f0bd1f1'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/8d9d9bf3565271ca7ab9c716a94e87296177e7ba'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/9ba6bb09e00b922d902f684f575779e5433fe6e3'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/cc024a3de265ef6c58957f4990eccb9f806208cb'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/f83b399aa05a0712e3b1569a30d3d90b3533d2ef'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://cert-portal.siemens.com/productcert/html/ssa-784472.html'
    label: 0b142b55-0307-4c5a-b3c9-f314f3fb7c5e
tags:
  - nvd
  - cve.org
epss: 0.00442
epssPercentile: 0.36786
ingestedAt: '2026-10-15T03:30:12.860Z'
---

## Overview

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

NFC: digital: Bounds check NFC-A cascade depth in SDD response handler

The NFC-A anti-collision cascade in digital_in_recv_sdd_res() appends 3
or 4 bytes to target->nfcid1 on each round, but the number of cascade
rounds is controlled entirely by the peer device.  The peer sets the
cascade tag in the SDD_RES (deciding 3 vs 4 bytes) and the
cascade-incomplete bit in the SEL_RES (deciding whether another round
follows).

ISO 14443-3 limits NFC-A to three cascade levels and target->nfcid1 is
sized accordingly (NFC_NFCID1_MAXSIZE = 10), but nothing in the driver
actually enforces this.  This means a malicious peer can keep the
cascade running, writing past the heap-allocated nfc_target with each
round.

Fix this by rejecting the response when the accumulated UID would exceed
the buffer.

Commit e329e71013c9 ("NFC: nci: Bounds check struct nfc_target arrays")
fixed similar missing checks against the same field on the NCI path.

## Affected

- `linux_kernel >= 3.13, < 6.6.136`
- `linux_kernel >= 6.7, < 6.12.83`
- `linux_kernel >= 6.13, < 6.18.24`
- `linux_kernel >= 6.19, < 6.19.14`
- `linux_kernel >= 7.0, < 7.0.1`

## Remediation

Upgrade past the affected range:

- `linux_kernel 7.0.1`