---
id: CVE-2026-89780
title: |-
  In the Linux kernel, the following vulnerability has been resolved:

  net: qualcomm: rmnet: restore skb->dev on deaggregated frames

  rmnet_map_deaggregate() allocates each sub-frame with alloc_skb() and
  leaves skb->dev NULL
summary: |-
  In the Linux kernel, the following vulnerability has been resolved:

  net: qualcomm: rmnet: restore skb->dev on deaggregated frames

  rmnet_map_deaggregate() allocates each sub-frame with alloc_skb() and
  leaves skb->dev NULL. __rmnet_map_i…
severity: none
vendor: Linux
product: Linux
affected:
  - >-
    Linux >= 378e25357ac78ad02fbc98bec9b4e3baaa916c5c <
    5aaa7409c1b4ca4c60d66e2afa99703bf4eb7ddd
  - >-
    Linux >= 378e25357ac78ad02fbc98bec9b4e3baaa916c5c <
    9b78ab84ddf97c06a8567edb62b6c0fd582f9a62
  - >-
    Linux >= 378e25357ac78ad02fbc98bec9b4e3baaa916c5c <
    9d18c6c6cd1666b2cb7915cad052e22abf520997
  - >-
    Linux >= 378e25357ac78ad02fbc98bec9b4e3baaa916c5c <
    4bcef54e4a3355a62d9ad90729fe563435ec76c3
  - >-
    Linux >= 378e25357ac78ad02fbc98bec9b4e3baaa916c5c <
    b14c22c31d9e30f38ea1693ac06d318f32258f5d
  - >-
    Linux >= 378e25357ac78ad02fbc98bec9b4e3baaa916c5c <
    7abe769e72c792e5f9eb273813eb3ecd8389854c
  - >-
    Linux >= 378e25357ac78ad02fbc98bec9b4e3baaa916c5c <
    200460a0793dc6af97d3b36d92ac245350ac26fc
  - >-
    Linux >= 378e25357ac78ad02fbc98bec9b4e3baaa916c5c <
    a66734a1c5e36525ea07e9f4547fddc51e916de3
  - Linux 4.17
published: '2026-09-16'
updated: '2026-09-16'
sourceUpdated: '2026-09-16T09:17:08.520'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-89780'
references:
  - url: 'https://git.kernel.org/stable/c/200460a0793dc6af97d3b36d92ac245350ac26fc'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/4bcef54e4a3355a62d9ad90729fe563435ec76c3'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/5aaa7409c1b4ca4c60d66e2afa99703bf4eb7ddd'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/7abe769e72c792e5f9eb273813eb3ecd8389854c'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/9b78ab84ddf97c06a8567edb62b6c0fd582f9a62'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/9d18c6c6cd1666b2cb7915cad052e22abf520997'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/a66734a1c5e36525ea07e9f4547fddc51e916de3'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/b14c22c31d9e30f38ea1693ac06d318f32258f5d'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
tags:
  - nvd
  - cve.org
ingestedAt: '2026-09-16T08:52:29.597Z'
epss: 0.0021
epssPercentile: 0.11557
---

## Overview

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

net: qualcomm: rmnet: restore skb->dev on deaggregated frames

rmnet_map_deaggregate() allocates each sub-frame with alloc_skb() and
leaves skb->dev NULL. __rmnet_map_ingress_handler() assigns
skb->dev = ep->egress_dev only on the data path, but a MAP command frame
is dispatched to rmnet_map_command() before that, so rmnet_map_send_ack()
runs netif_tx_lock(skb->dev) on a NULL device. An unprivileged user
reaches this by unsharing a user+net namespace, creating an rmnet link
over a tap device with INGRESS_DEAGGREGATION and INGRESS_MAP_COMMANDS,
and writing an aggregated frame carrying a flow-control command to the
tap fd.

Restore the assignment dropped by 378e25357ac7, so every skb leaving
rmnet_map_deaggregate() has a valid device.

  BUG: KASAN: null-ptr-deref in _raw_spin_lock (kernel/locking/spinlock.c:158)
  Write of size 4 at addr 00000000000004b4 by task exploit/144
  Call Trace:
   _raw_spin_lock (kernel/locking/spinlock.c:158)
   netif_tx_lock (net/sched/sch_generic.c:497)
   rmnet_map_command (drivers/net/ethernet/qualcomm/rmnet/rmnet_map_command.c:67)
   rmnet_rx_handler (drivers/net/ethernet/qualcomm/rmnet/rmnet_handlers.c:125)
   __netif_receive_skb_core.constprop.0 (net/core/dev.c:6103)
   ...
   __netif_receive_skb_one_core (net/core/dev.c:6214)
   netif_receive_skb (net/core/dev.c:6474)
   tun_get_user (drivers/net/tun.c:1966)
   tun_chr_write_iter (drivers/net/tun.c:2012)
   vfs_write (fs/read_write.c:687)
   ksys_write (fs/read_write.c:739)
   do_syscall_64 (arch/x86/entry/syscall_64.c:94)
   entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:121)
  Kernel panic - not syncing: Fatal exception in interrupt

## Remediation

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