---
id: CVE-2026-98567
title: 'net: xps: reject an out of range traffic class'
summary: |-
  In the Linux kernel, the following vulnerability has been resolved:

  net: xps: reject an out of range traffic class

  Only the entries below dev->num_tc are valid in dev->tc_to_txq[], and
  dev->prio_tc_map[] may only name classes below it.…
severity: none
vendor: Linux
product: Linux
affected:
  - >-
    Linux >= 184c449f91fef521042970cca46bd5cdfc0e3a37 <
    967e10f40a0c6732db299cbe001df0e859196055
  - >-
    Linux >= 184c449f91fef521042970cca46bd5cdfc0e3a37 <
    1cb8e40525a72c9f1e1cf94c68c172b3b9bbdc81
  - >-
    Linux >= 184c449f91fef521042970cca46bd5cdfc0e3a37 <
    6ea8f643053f33622f9116e4e1db58306ece45e3
  - >-
    Linux >= 184c449f91fef521042970cca46bd5cdfc0e3a37 <
    9e841723ba482d41ecbf90241c756a16cdfea949
  - >-
    Linux >= 184c449f91fef521042970cca46bd5cdfc0e3a37 <
    eff227a3cb4d0089fbb85c73480bf8abf2e5ae7f
  - >-
    Linux >= 184c449f91fef521042970cca46bd5cdfc0e3a37 <
    2cc1c3977acbffc417fb5b57699d1df3dcffb5fd
  - >-
    Linux >= 184c449f91fef521042970cca46bd5cdfc0e3a37 <
    930318290d8509e864c015fe6c9239470b3c579c
  - >-
    Linux >= 184c449f91fef521042970cca46bd5cdfc0e3a37 <
    4da3b7b8b50f3e2fde54a4c18a82a8e3f6223910
  - Linux 4.10
published: '2026-10-18'
updated: '2026-10-18'
sourceUpdated: '2026-10-18T15:18:33.721Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-98567'
references:
  - url: 'https://git.kernel.org/stable/c/967e10f40a0c6732db299cbe001df0e859196055'
  - url: 'https://git.kernel.org/stable/c/1cb8e40525a72c9f1e1cf94c68c172b3b9bbdc81'
  - url: 'https://git.kernel.org/stable/c/6ea8f643053f33622f9116e4e1db58306ece45e3'
  - url: 'https://git.kernel.org/stable/c/9e841723ba482d41ecbf90241c756a16cdfea949'
  - url: 'https://git.kernel.org/stable/c/eff227a3cb4d0089fbb85c73480bf8abf2e5ae7f'
  - url: 'https://git.kernel.org/stable/c/2cc1c3977acbffc417fb5b57699d1df3dcffb5fd'
  - url: 'https://git.kernel.org/stable/c/930318290d8509e864c015fe6c9239470b3c579c'
  - url: 'https://git.kernel.org/stable/c/4da3b7b8b50f3e2fde54a4c18a82a8e3f6223910'
tags:
  - cve.org
ingestedAt: '2026-10-18T15:45:12.259Z'
---

## Overview

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

net: xps: reject an out of range traffic class

Only the entries below dev->num_tc are valid in dev->tc_to_txq[], and
dev->prio_tc_map[] may only name classes below it. netdev_set_num_tc()
lowers dev->num_tc without touching either array.

netdev_txq_to_tc() walks all TC_MAX_QUEUE slots and
netdev_get_prio_tc_map() returns the entry as it stands, so a leftover
entry is handed out as a traffic class >= dev->num_tc. Taking that
class from netdev_txq_to_tc(), __netif_set_xps_queue() rejects only a
negative one and indexes an XPS map sized for dev->num_tc classes:

	tci = j * num_tc + tc;
	RCU_INIT_POINTER(new_dev_maps->attr_map[tci], map);

attr_map[] holds nr_ids * num_tc entries and j runs over the ids named
in the mask, so a class that is not below num_tc pushes tci past the end
of the map for the last ids and the store overruns it.

Any caller that lowers num_tc leaves such entries behind, and
mqprio_destroy() tears down with netdev_set_num_tc(dev, 0) rather than
netdev_reset_tc(). After mqprio with 8 classes then 1, tc_to_txq[1..7]
still describe txq 1..7. The splat is from an XPS write to txq 2 on a
veth with 8 rx queues: attr_map[] has 8 * 1 entries, tci = j + 2, and
j == 6 stores one past the end of the 88-byte map:

  BUG: KASAN: slab-out-of-bounds in __netif_set_xps_queue (net/core/dev.c:2954)
  Write of size 8 at addr ffff88813016bc58 by task xps_oob/634
   __netif_set_xps_queue (net/core/dev.c:2954)
   xps_rxqs_store (net/core/net-sysfs.c:1880)
   netdev_queue_attr_store (net/core/net-sysfs.c:1390)
  Allocated by task 634:
   __kmalloc_noprof (mm/slub.c:5439)
   __netif_set_xps_queue (net/core/dev.c:2937)
  The buggy address is located 0 bytes to the right of
   allocated 88-byte region [ffff88813016bc00, ffff88813016bc58)

Reject a class the map has no room for.

## Affected

- `Linux >= 184c449f91fef521042970cca46bd5cdfc0e3a37 < 967e10f40a0c6732db299cbe001df0e859196055`
- `Linux >= 184c449f91fef521042970cca46bd5cdfc0e3a37 < 1cb8e40525a72c9f1e1cf94c68c172b3b9bbdc81`
- `Linux >= 184c449f91fef521042970cca46bd5cdfc0e3a37 < 6ea8f643053f33622f9116e4e1db58306ece45e3`
- `Linux >= 184c449f91fef521042970cca46bd5cdfc0e3a37 < 9e841723ba482d41ecbf90241c756a16cdfea949`
- `Linux >= 184c449f91fef521042970cca46bd5cdfc0e3a37 < eff227a3cb4d0089fbb85c73480bf8abf2e5ae7f`
- `Linux >= 184c449f91fef521042970cca46bd5cdfc0e3a37 < 2cc1c3977acbffc417fb5b57699d1df3dcffb5fd`
- `Linux >= 184c449f91fef521042970cca46bd5cdfc0e3a37 < 930318290d8509e864c015fe6c9239470b3c579c`
- `Linux >= 184c449f91fef521042970cca46bd5cdfc0e3a37 < 4da3b7b8b50f3e2fde54a4c18a82a8e3f6223910`
- `Linux 4.10`

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.