---
id: CVE-2026-46259
title: 'procfs: fix missing RCU protection when reading real_parent in do_task_stat()'
summary: |-
  In the Linux kernel, the following vulnerability has been resolved:

  procfs: fix missing RCU protection when reading real_parent in do_task_stat()

  When reading /proc/[pid]/stat, do_task_stat() accesses task->real_parent
  without proper R…
severity: high
cvss: 7.8
cvssVector: 'CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H'
cvssSource: cna
vendor: Linux
product: Linux
affected:
  - >-
    Linux >= 06fffb1267c9d986687b69d74a46ee332a50575e <
    fefa0fcd78be465b7ad4c497fa6ec90d64194c04
  - >-
    Linux >= 06fffb1267c9d986687b69d74a46ee332a50575e <
    c93a33f28f915d446eea6fb3f0e1def0b3af1982
  - >-
    Linux >= 06fffb1267c9d986687b69d74a46ee332a50575e <
    1c8dc5b5517546c68ffae40b948336122bb61306
  - >-
    Linux >= 06fffb1267c9d986687b69d74a46ee332a50575e <
    0e64bd46a04a4fd61279aca9f53a664e9e5f7e7e
  - >-
    Linux >= 06fffb1267c9d986687b69d74a46ee332a50575e <
    73ec7c96601d61d52310c659145bb06d933a0fa6
  - >-
    Linux >= 06fffb1267c9d986687b69d74a46ee332a50575e <
    4f9ae386861e280b7631ca252f798d25575627ee
  - >-
    Linux >= 06fffb1267c9d986687b69d74a46ee332a50575e <
    dd8b13cb4ff1a4545a214ed897fdf2bc341155b6
  - >-
    Linux >= 06fffb1267c9d986687b69d74a46ee332a50575e <
    76149d53502cf17ef3ae454ff384551236fba867
  - Linux 2.6.26
ssvc:
  exploitation: none
  automatable: 'no'
  technicalImpact: total
  timestamp: '2026-10-16T15:21:25.410048Z'
published: '2026-06-03'
updated: '2026-10-16'
sourceUpdated: '2026-10-16T15:31:14.530Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-46259'
references:
  - url: 'https://git.kernel.org/stable/c/fefa0fcd78be465b7ad4c497fa6ec90d64194c04'
  - url: 'https://git.kernel.org/stable/c/c93a33f28f915d446eea6fb3f0e1def0b3af1982'
  - url: 'https://git.kernel.org/stable/c/1c8dc5b5517546c68ffae40b948336122bb61306'
  - url: 'https://git.kernel.org/stable/c/0e64bd46a04a4fd61279aca9f53a664e9e5f7e7e'
  - url: 'https://git.kernel.org/stable/c/73ec7c96601d61d52310c659145bb06d933a0fa6'
  - url: 'https://git.kernel.org/stable/c/4f9ae386861e280b7631ca252f798d25575627ee'
  - url: 'https://git.kernel.org/stable/c/dd8b13cb4ff1a4545a214ed897fdf2bc341155b6'
  - url: 'https://git.kernel.org/stable/c/76149d53502cf17ef3ae454ff384551236fba867'
tags:
  - cve.org
epss: 0.00176
epssPercentile: 0.06636
ingestedAt: '2026-10-16T17:24:46.713Z'
---

## Overview

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

procfs: fix missing RCU protection when reading real_parent in do_task_stat()

When reading /proc/[pid]/stat, do_task_stat() accesses task->real_parent
without proper RCU protection, which leads to:

  cpu 0                               cpu 1
  -----                               -----
  do_task_stat
    var = task->real_parent
                                      release_task
                                        call_rcu(delayed_put_task_struct)
    task_tgid_nr_ns(var)
      rcu_read_lock   <--- Too late to protect task->real_parent!
      task_pid_ptr    <--- UAF!
      rcu_read_unlock

This patch uses task_ppid_nr_ns() instead of task_tgid_nr_ns() to add
proper RCU protection for accessing task->real_parent.

## Affected

- `Linux >= 06fffb1267c9d986687b69d74a46ee332a50575e < fefa0fcd78be465b7ad4c497fa6ec90d64194c04`
- `Linux >= 06fffb1267c9d986687b69d74a46ee332a50575e < c93a33f28f915d446eea6fb3f0e1def0b3af1982`
- `Linux >= 06fffb1267c9d986687b69d74a46ee332a50575e < 1c8dc5b5517546c68ffae40b948336122bb61306`
- `Linux >= 06fffb1267c9d986687b69d74a46ee332a50575e < 0e64bd46a04a4fd61279aca9f53a664e9e5f7e7e`
- `Linux >= 06fffb1267c9d986687b69d74a46ee332a50575e < 73ec7c96601d61d52310c659145bb06d933a0fa6`
- `Linux >= 06fffb1267c9d986687b69d74a46ee332a50575e < 4f9ae386861e280b7631ca252f798d25575627ee`
- `Linux >= 06fffb1267c9d986687b69d74a46ee332a50575e < dd8b13cb4ff1a4545a214ed897fdf2bc341155b6`
- `Linux >= 06fffb1267c9d986687b69d74a46ee332a50575e < 76149d53502cf17ef3ae454ff384551236fba867`
- `Linux 2.6.26`

## Remediation

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