---
id: CVE-2023-53578
title: 'net: qrtr: Fix an uninit variable access bug in qrtr_tx_resume()'
summary: |-
  In the Linux kernel, the following vulnerability has been resolved:

  net: qrtr: Fix an uninit variable access bug in qrtr_tx_resume()

  Syzbot reported a bug as following:

  =====================================================
  BUG: KMSAN:…
severity: none
vendor: Linux
product: Linux
affected:
  - >-
    Linux >= 5fdeb0d372ab33b4175043a2a4a1730239a217f1 <
    3814d211ff13ee35f2d9437439a6c7df58524137
  - >-
    Linux >= 5fdeb0d372ab33b4175043a2a4a1730239a217f1 <
    c6a796ee5a639ffb83c6e5469408cc2ec16cac6a
  - >-
    Linux >= 5fdeb0d372ab33b4175043a2a4a1730239a217f1 <
    bef57c227b52c2bde00fad33556175d36d12cfa0
  - >-
    Linux >= 5fdeb0d372ab33b4175043a2a4a1730239a217f1 <
    8c9ce34a6ff2c544f96ce0b088e8fd3c1b9698c4
  - >-
    Linux >= 5fdeb0d372ab33b4175043a2a4a1730239a217f1 <
    6417070918de3bcdbe0646e7256dae58fd8083ba
  - Linux 5.6
ssvc:
  exploitation: none
  automatable: 'no'
  technicalImpact: partial
  timestamp: '2026-11-05T20:24:21.438547Z'
published: '2025-10-04'
updated: '2026-11-05'
sourceUpdated: '2026-11-05T20:31:15.588Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2023-53578'
references:
  - url: 'https://git.kernel.org/stable/c/3814d211ff13ee35f2d9437439a6c7df58524137'
  - url: 'https://git.kernel.org/stable/c/c6a796ee5a639ffb83c6e5469408cc2ec16cac6a'
  - url: 'https://git.kernel.org/stable/c/bef57c227b52c2bde00fad33556175d36d12cfa0'
  - url: 'https://git.kernel.org/stable/c/8c9ce34a6ff2c544f96ce0b088e8fd3c1b9698c4'
  - url: 'https://git.kernel.org/stable/c/6417070918de3bcdbe0646e7256dae58fd8083ba'
tags:
  - cve.org
epss: 0.00156
epssPercentile: 0.04792
ingestedAt: '2026-11-05T22:38:31.813Z'
---

## Overview

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

net: qrtr: Fix an uninit variable access bug in qrtr_tx_resume()

Syzbot reported a bug as following:

=====================================================
BUG: KMSAN: uninit-value in qrtr_tx_resume+0x185/0x1f0 net/qrtr/af_qrtr.c:230
 qrtr_tx_resume+0x185/0x1f0 net/qrtr/af_qrtr.c:230
 qrtr_endpoint_post+0xf85/0x11b0 net/qrtr/af_qrtr.c:519
 qrtr_tun_write_iter+0x270/0x400 net/qrtr/tun.c:108
 call_write_iter include/linux/fs.h:2189 [inline]
 aio_write+0x63a/0x950 fs/aio.c:1600
 io_submit_one+0x1d1c/0x3bf0 fs/aio.c:2019
 __do_sys_io_submit fs/aio.c:2078 [inline]
 __se_sys_io_submit+0x293/0x770 fs/aio.c:2048
 __x64_sys_io_submit+0x92/0xd0 fs/aio.c:2048
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd

Uninit was created at:
 slab_post_alloc_hook mm/slab.h:766 [inline]
 slab_alloc_node mm/slub.c:3452 [inline]
 __kmem_cache_alloc_node+0x71f/0xce0 mm/slub.c:3491
 __do_kmalloc_node mm/slab_common.c:967 [inline]
 __kmalloc_node_track_caller+0x114/0x3b0 mm/slab_common.c:988
 kmalloc_reserve net/core/skbuff.c:492 [inline]
 __alloc_skb+0x3af/0x8f0 net/core/skbuff.c:565
 __netdev_alloc_skb+0x120/0x7d0 net/core/skbuff.c:630
 qrtr_endpoint_post+0xbd/0x11b0 net/qrtr/af_qrtr.c:446
 qrtr_tun_write_iter+0x270/0x400 net/qrtr/tun.c:108
 call_write_iter include/linux/fs.h:2189 [inline]
 aio_write+0x63a/0x950 fs/aio.c:1600
 io_submit_one+0x1d1c/0x3bf0 fs/aio.c:2019
 __do_sys_io_submit fs/aio.c:2078 [inline]
 __se_sys_io_submit+0x293/0x770 fs/aio.c:2048
 __x64_sys_io_submit+0x92/0xd0 fs/aio.c:2048
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd

It is because that skb->len requires at least sizeof(struct qrtr_ctrl_pkt)
in qrtr_tx_resume(). And skb->len equals to size in qrtr_endpoint_post().
But size is less than sizeof(struct qrtr_ctrl_pkt) when qrtr_cb->type
equals to QRTR_TYPE_RESUME_TX in qrtr_endpoint_post() under the syzbot
scenario. This triggers the uninit variable access bug.

Add size check when qrtr_cb->type equals to QRTR_TYPE_RESUME_TX in
qrtr_endpoint_post() to fix the bug.

## Affected

- `Linux >= 5fdeb0d372ab33b4175043a2a4a1730239a217f1 < 3814d211ff13ee35f2d9437439a6c7df58524137`
- `Linux >= 5fdeb0d372ab33b4175043a2a4a1730239a217f1 < c6a796ee5a639ffb83c6e5469408cc2ec16cac6a`
- `Linux >= 5fdeb0d372ab33b4175043a2a4a1730239a217f1 < bef57c227b52c2bde00fad33556175d36d12cfa0`
- `Linux >= 5fdeb0d372ab33b4175043a2a4a1730239a217f1 < 8c9ce34a6ff2c544f96ce0b088e8fd3c1b9698c4`
- `Linux >= 5fdeb0d372ab33b4175043a2a4a1730239a217f1 < 6417070918de3bcdbe0646e7256dae58fd8083ba`
- `Linux 5.6`

## Remediation

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