---
id: CVE-2022-50073
title: >-
  In the Linux kernel, the following vulnerability has been resolved:


  net: tap: NULL pointer derefence in dev_parse_header_protocol when skb->dev is
  null


  Fixes a NULL pointer derefence bug triggered from tap driver.

  When tap_get_user cal…
summary: >-
  In the Linux kernel, the following vulnerability has been resolved:


  net: tap: NULL pointer derefence in dev_parse_header_protocol when skb->dev is
  null


  Fixes a NULL pointer derefence bug triggered from tap driver.

  When tap_get_user cal…
severity: medium
cvss: 5.5
cvssVector: 'CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H'
cwe:
  - CWE-476
vendor: linux
product: linux_kernel
affected:
  - 'linux_kernel >= 4.14.226, < 4.15'
  - 'linux_kernel >= 4.19.181, < 4.20'
  - 'linux_kernel >= 5.4.106, < 5.5'
  - 'linux_kernel >= 5.10.24, < 5.11'
  - 'linux_kernel >= 5.11.7, < 5.12'
  - 'linux_kernel >= 5.12.1, < 5.19.4'
  - linux_kernel = 5.12
patched:
  - linux_kernel 5.19.4
published: '2025-06-18'
updated: '2026-08-12'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2022-50073'
references:
  - url: 'https://git.kernel.org/stable/c/447ba770cfe798925f4923548b367fd49f0ee5f0'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/4f61f133f354853bc394ec7d6028adb9b02dd701'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/8f90163f9e013c8fc791aab338aab44a46044cfc'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/dd29648fcf69339713f2d25f7014ae905dcdfc18'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'http://www.openwall.com/lists/oss-security/2026/08/12/20'
    label: af854a3a-2127-422b-91ae-364da2661108
tags:
  - nvd
epss: 0.00201
epssPercentile: 0.08933
ingestedAt: '2026-08-12T19:54:26.327Z'
---

## Overview

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

net: tap: NULL pointer derefence in dev_parse_header_protocol when skb->dev is null

Fixes a NULL pointer derefence bug triggered from tap driver.
When tap_get_user calls virtio_net_hdr_to_skb the skb->dev is null
(in tap.c skb->dev is set after the call to virtio_net_hdr_to_skb)
virtio_net_hdr_to_skb calls dev_parse_header_protocol which
needs skb->dev field to be valid.

The line that trigers the bug is in dev_parse_header_protocol
(dev is at offset 0x10 from skb and is stored in RAX register)
  if (!dev->header_ops || !dev->header_ops->parse_protocol)
  22e1:   mov    0x10(%rbx),%rax
  22e5:	  mov    0x230(%rax),%rax

Setting skb->dev before the call in tap.c fixes the issue.

BUG: kernel NULL pointer dereference, address: 0000000000000230
RIP: 0010:virtio_net_hdr_to_skb.constprop.0+0x335/0x410 [tap]
Code: c0 0f 85 b7 fd ff ff eb d4 41 39 c6 77 cf 29 c6 48 89 df 44 01 f6 e8 7a 79 83 c1 48 85 c0 0f 85 d9 fd ff ff eb b7 48 8b 43 10 <48> 8b 80 30 02 00 00 48 85 c0 74 55 48 8b 40 28 48 85 c0 74 4c 48
RSP: 0018:ffffc90005c27c38 EFLAGS: 00010246
RAX: 0000000000000000 RBX: ffff888298f25300 RCX: 0000000000000010
RDX: 0000000000000005 RSI: ffffc90005c27cb6 RDI: ffff888298f25300
RBP: ffffc90005c27c80 R08: 00000000ffffffea R09: 00000000000007e8
R10: ffff88858ec77458 R11: 0000000000000000 R12: 0000000000000001
R13: 0000000000000014 R14: ffffc90005c27e08 R15: ffffc90005c27cb6
FS:  0000000000000000(0000) GS:ffff88858ec40000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000230 CR3: 0000000281408006 CR4: 00000000003706e0
Call Trace:
 tap_get_user+0x3f1/0x540 [tap]
 tap_sendmsg+0x56/0x362 [tap]
 ? get_tx_bufs+0xc2/0x1e0 [vhost_net]
 handle_tx_copy+0x114/0x670 [vhost_net]
 handle_tx+0xb0/0xe0 [vhost_net]
 handle_tx_kick+0x15/0x20 [vhost_net]
 vhost_worker+0x7b/0xc0 [vhost]
 ? vhost_vring_call_reset+0x40/0x40 [vhost]
 kthread+0xfa/0x120
 ? kthread_complete_and_exit+0x20/0x20
 ret_from_fork+0x1f/0x30

## Affected

- `linux_kernel >= 4.14.226, < 4.15`
- `linux_kernel >= 4.19.181, < 4.20`
- `linux_kernel >= 5.4.106, < 5.5`
- `linux_kernel >= 5.10.24, < 5.11`
- `linux_kernel >= 5.11.7, < 5.12`
- `linux_kernel >= 5.12.1, < 5.19.4`
- `linux_kernel = 5.12`

## Remediation

Upgrade past the affected range:

- `linux_kernel 5.19.4`