---
id: CVE-2026-89973
title: |-
  In the Linux kernel, the following vulnerability has been resolved:

  nvme-tcp: check the data direction of a C2HData PDU

  nvme_tcp_handle_c2h_data() finds the request by command id and checks
  that it has a payload, but it does not check …
summary: |-
  In the Linux kernel, the following vulnerability has been resolved:

  nvme-tcp: check the data direction of a C2HData PDU

  nvme_tcp_handle_c2h_data() finds the request by command id and checks
  that it has a payload, but it does not check …
severity: high
cvss: 8.2
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:H'
vendor: Linux
product: Linux
affected:
  - >-
    Linux >= 3f2304f8c6d6ed97849057bd16fee99e434ca796 <
    df74950ba6008655d4a977d17df7faf4b6e52b74
  - >-
    Linux >= 3f2304f8c6d6ed97849057bd16fee99e434ca796 <
    980d990f3c0560d7dfbfbf14699651fdf02f26ee
  - >-
    Linux >= 3f2304f8c6d6ed97849057bd16fee99e434ca796 <
    5b115d932f6e769ac80783fb18edd21b0aed256e
  - >-
    Linux >= 3f2304f8c6d6ed97849057bd16fee99e434ca796 <
    0673a2affe45ca76b60de31a83c67b1e60f81bde
  - >-
    Linux >= 3f2304f8c6d6ed97849057bd16fee99e434ca796 <
    80d56202fbdff8906be6954b2776e5c14a4026f2
  - >-
    Linux >= 3f2304f8c6d6ed97849057bd16fee99e434ca796 <
    b4af7999a998787d5eb6facb5a333e04a4f1d2d9
  - >-
    Linux >= 3f2304f8c6d6ed97849057bd16fee99e434ca796 <
    a0c389b8a495bda1eb719d2503853c924b7a8355
  - >-
    Linux >= 3f2304f8c6d6ed97849057bd16fee99e434ca796 <
    f83af377c148f6ad94b41c0e8313f12adf45e1c1
  - Linux 5.0
published: '2026-09-16'
updated: '2026-09-16'
sourceUpdated: '2026-09-16T15:18:21.747'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-89973'
references:
  - url: 'https://git.kernel.org/stable/c/0673a2affe45ca76b60de31a83c67b1e60f81bde'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/5b115d932f6e769ac80783fb18edd21b0aed256e'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/80d56202fbdff8906be6954b2776e5c14a4026f2'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/980d990f3c0560d7dfbfbf14699651fdf02f26ee'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/a0c389b8a495bda1eb719d2503853c924b7a8355'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/b4af7999a998787d5eb6facb5a333e04a4f1d2d9'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/df74950ba6008655d4a977d17df7faf4b6e52b74'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/f83af377c148f6ad94b41c0e8313f12adf45e1c1'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
tags:
  - nvd
  - cve.org
ingestedAt: '2026-09-16T10:53:53.955Z'
epss: 0.00633
epssPercentile: 0.48156
---

## Overview

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

nvme-tcp: check the data direction of a C2HData PDU

nvme_tcp_handle_c2h_data() finds the request by command id and checks
that it has a payload, but it does not check that the command asked for
data to be read.  A controller that answers a write command with C2HData
therefore reaches nvme_tcp_recv_data(), where _copy_to_iter() hits
WARN_ON_ONCE(i->data_source) and returns 0.  The receive path turns that
into -EFAULT and resets the controller.

No data is copied, so this is not memory corruption.  What a controller
gets is a kernel warning it can raise at will, which is fatal on a host
booted with panic_on_warn.

The send path already knows the direction - it consults rq_data_dir()
when it builds a command - and nvme_tcp_handle_r2t() checks the length
and the offset of the request it names.  The C2HData path does not check
the direction at all.

Reject a C2HData PDU whose command is not a read.  Rejecting it fails
the command and resets the controller, as the neighbouring check in this
function does; what goes away is the warning.

  [    6.885580] ------------[ cut here ]------------
  [    6.886457] WARNING: lib/iov_iter.c:193 at _copy_to_iter+0x289/0x1330, CPU#0: kworker/0:1H/71
  [    6.888137] CPU: 0 UID: 0 PID: 71 Comm: kworker/0:1H Not tainted 7.2.0-rc5-NVMETCP-gf5098b6bae76 #1 PREEMPT(lazy)
  [    6.891165] Workqueue: nvme_tcp_wq nvme_tcp_io_work
  [    6.891875] RIP: 0010:_copy_to_iter+0x289/0x1330
  [    6.903739] Call Trace:
  [    6.904085]  <TASK>
  [    6.909254]  __skb_datagram_iter+0x433/0x820
  [    6.911026]  skb_copy_datagram_iter+0x37/0x120
  [    6.911622]  nvme_tcp_recv_skb+0xa07/0x4320
  [    6.913378]  __tcp_read_sock+0x1ab/0x810
  [    6.915788]  nvme_tcp_try_recv+0x152/0x1e0
  [    6.918222]  nvme_tcp_io_work+0x1e4/0x6c0
  [    6.926906]  </TASK>
  [    6.927226] ---[ end trace 0000000000000000 ]---
  [    6.927878] nvme nvme0: queue 1 failed to copy request 0x71 data
  [    6.928709] nvme nvme0: receive failed:  -14

## Remediation

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