---
id: CVE-2026-89789
title: >-
  In the Linux kernel, the following vulnerability has been resolved:


  gtp: add synchronize_net() in gtp_newlink() error path to prevent
  use-after-free


  gtp_newlink()'s error path frees tid_hash and addr_hash without

  waiting for an RCU gra…
summary: >-
  In the Linux kernel, the following vulnerability has been resolved:


  gtp: add synchronize_net() in gtp_newlink() error path to prevent
  use-after-free


  gtp_newlink()'s error path frees tid_hash and addr_hash without

  waiting for an RCU gra…
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'
vendor: Linux
product: Linux
affected:
  - >-
    Linux >= 459aa660eb1d8ce67080da1983bb81d716aa5a69 <
    fcafb2b1430824bae4258c01a439ec97ca0c6973
  - >-
    Linux >= 459aa660eb1d8ce67080da1983bb81d716aa5a69 <
    3ca3da5c305caa873ddb81e8c6b118143f6dd3d1
  - >-
    Linux >= 459aa660eb1d8ce67080da1983bb81d716aa5a69 <
    6f815c2fb6ab20385f81c353cdad0ea3b88132af
  - >-
    Linux >= 459aa660eb1d8ce67080da1983bb81d716aa5a69 <
    e3b9aa0773abd5d4ed90be41ce5306c146d5b09e
  - >-
    Linux >= 459aa660eb1d8ce67080da1983bb81d716aa5a69 <
    fd8396cfecbd904468c71362f08aaa25f96d5337
  - >-
    Linux >= 459aa660eb1d8ce67080da1983bb81d716aa5a69 <
    7677eb2cbf2cc7446de474c01a6b06277c0051e5
  - >-
    Linux >= 459aa660eb1d8ce67080da1983bb81d716aa5a69 <
    8d85498016a5bb56339734a14c276209fa65bafc
  - >-
    Linux >= 459aa660eb1d8ce67080da1983bb81d716aa5a69 <
    d989e22ae9802c52c56ad4284d0caf26696cf6ae
  - Linux 4.7
published: '2026-09-16'
updated: '2026-09-16'
sourceUpdated: '2026-09-16T15:18:09.107'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-89789'
references:
  - url: 'https://git.kernel.org/stable/c/3ca3da5c305caa873ddb81e8c6b118143f6dd3d1'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/6f815c2fb6ab20385f81c353cdad0ea3b88132af'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/7677eb2cbf2cc7446de474c01a6b06277c0051e5'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/8d85498016a5bb56339734a14c276209fa65bafc'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/d989e22ae9802c52c56ad4284d0caf26696cf6ae'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/e3b9aa0773abd5d4ed90be41ce5306c146d5b09e'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/fcafb2b1430824bae4258c01a439ec97ca0c6973'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/fd8396cfecbd904468c71362f08aaa25f96d5337'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
tags:
  - nvd
  - cve.org
ingestedAt: '2026-09-16T08:52:29.591Z'
epss: 0.00171
epssPercentile: 0.05681
---

## Overview

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

gtp: add synchronize_net() in gtp_newlink() error path to prevent use-after-free

gtp_newlink()'s error path frees tid_hash and addr_hash without
waiting for an RCU grace period after clearing sk_user_data. A
concurrent gtp_encap_recv() in softirq may still hold the gtp_dev
pointer obtained via rcu_dereference_sk_user_data() and access the
freed memory.

  BUG: KASAN: slab-use-after-free in gtp0_pdp_find+0x1f6/0x200 (gtp.c:152)
  Call Trace:
   <IRQ>
   gtp0_pdp_find+0x1f6/0x200
   gtp_encap_recv+0x527/0x24b0
   udp_queue_rcv_one_skb+0x75f/0xc10

Add synchronize_net() before the kfree calls in out_hashtable, which
covers all error paths from both gtp_encap_enable() and
gtp_create_sockets().

## Remediation

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