---
id: CVE-2026-98150
title: |-
  In the Linux kernel, the following vulnerability has been resolved:

  bpf: Fix BPF_F_CPU validation for sparse CPU IDs

  BPF_F_CPU stores the target CPU ID in the upper 32 bits of the map
  operation flags
summary: |-
  In the Linux kernel, the following vulnerability has been resolved:

  bpf: Fix BPF_F_CPU validation for sparse CPU IDs

  BPF_F_CPU stores the target CPU ID in the upper 32 bits of the map
  operation flags. bpf_map_check_op_flags() currently…
severity: high
cvss: 7
cvssVector: 'CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H'
vendor: Linux
product: Linux
affected:
  - >-
    Linux >= 2b421662c7887a0649fe409155a1f101562d0fa9 <
    bdc5941f6eeef90b76a07fd8ca38ac1933ba2195
  - >-
    Linux >= 2b421662c7887a0649fe409155a1f101562d0fa9 <
    ed54bf564ac52699cf4def3d0c2125d493e756f9
  - Linux 7.0
published: '2026-09-25'
updated: '2026-09-25'
sourceUpdated: '2026-09-25T15:18:06.997'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-98150'
references:
  - url: 'https://git.kernel.org/stable/c/bdc5941f6eeef90b76a07fd8ca38ac1933ba2195'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/ed54bf564ac52699cf4def3d0c2125d493e756f9'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
tags:
  - nvd
  - cve.org
ingestedAt: '2026-09-25T11:06:38.806Z'
---

## Overview

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

bpf: Fix BPF_F_CPU validation for sparse CPU IDs

BPF_F_CPU stores the target CPU ID in the upper 32 bits of the map
operation flags. bpf_map_check_op_flags() currently compares that ID
with num_possible_cpus(), which is the number of possible CPUs rather
than a bound on CPU IDs.

On an arm64 QEMU guest with a CPU device-tree hole, the possible CPU
mask was 0,2-3. A userspace program using raw bpf() syscalls creates
a BPF_MAP_TYPE_PERCPU_ARRAY and performs update and lookup operations
for each CPU by setting BPF_F_CPU and the CPU ID in the flags.

With the old check, CPU 1 is incorrectly accepted while valid CPU 3 is
rejected with -ERANGE. The CPU 1 update then reaches the per-CPU map
access path and triggers:

  Unable to handle kernel paging request at virtual address ...
  pc : __pi_memcpy_generic+0x5c/0x22c
  lr : bpf_percpu_array_update+0x2dc/0x2e8
  Call trace:
    __pi_memcpy_generic
    bpf_map_update_value
    map_update_elem
    __sys_bpf

Check the CPU ID against nr_cpu_ids and cpu_possible() instead. This
rejects CPU IDs outside the valid range and CPUs absent from the
possible mask, while allowing valid sparse CPU IDs.

## Remediation

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