---
id: CVE-2026-99167
title: 'net/sched: fix use-after-free in __tcf_action_put()'
summary: |-
  In the Linux kernel, the following vulnerability has been resolved:

  net/sched: fix use-after-free in __tcf_action_put()

  __tcf_action_put() decrements the reference count before decrementing the
  binding count. Another thread can free th…
severity: none
vendor: Linux
product: Linux
affected:
  - >-
    Linux >= 16af6067392c40e454e49eec834843ab03643d96 <
    2465d27ef90de9105c2bffb6c35f8ce08918e642
  - >-
    Linux >= 16af6067392c40e454e49eec834843ab03643d96 <
    2e012e431aa271ef3c84206f48854f539c03bff0
  - >-
    Linux >= 16af6067392c40e454e49eec834843ab03643d96 <
    7b16eb911091aae237a8673da94e4dfb9cd21d54
  - Linux 4.19
published: '2026-10-28'
updated: '2026-10-28'
sourceUpdated: '2026-10-28T10:35:18.850Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-99167'
references:
  - url: 'https://git.kernel.org/stable/c/2465d27ef90de9105c2bffb6c35f8ce08918e642'
  - url: 'https://git.kernel.org/stable/c/2e012e431aa271ef3c84206f48854f539c03bff0'
  - url: 'https://git.kernel.org/stable/c/7b16eb911091aae237a8673da94e4dfb9cd21d54'
tags:
  - cve.org
ingestedAt: '2026-10-28T11:09:40.389Z'
---

## Overview

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

net/sched: fix use-after-free in __tcf_action_put()

__tcf_action_put() decrements the reference count before decrementing the
binding count. Another thread can free the action between these operations,
causing the binding-count update to access freed memory. KASAN reports it
as:

  BUG: KASAN: slab-use-after-free in __tcf_action_put+0x327/0x340
  Write of size 4 at addr ff11000000d46420 by task tc-put-pause/64

Hold the action IDR mutex across both counter updates and IDR removal,
keeping cleanup outside the lock.

## Affected

- `Linux >= 16af6067392c40e454e49eec834843ab03643d96 < 2465d27ef90de9105c2bffb6c35f8ce08918e642`
- `Linux >= 16af6067392c40e454e49eec834843ab03643d96 < 2e012e431aa271ef3c84206f48854f539c03bff0`
- `Linux >= 16af6067392c40e454e49eec834843ab03643d96 < 7b16eb911091aae237a8673da94e4dfb9cd21d54`
- `Linux 4.19`

## Remediation

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