---
id: CVE-2026-98479
title: 'scsi: libiscsi_tcp: Check the data direction of a Data-In PDU'
summary: |-
  In the Linux kernel, the following vulnerability has been resolved:

  scsi: libiscsi_tcp: Check the data direction of a Data-In PDU

  The Data-In branch of iscsi_tcp_hdr_dissect() resolves the ITT to a task
  and copies the PDU's data segmen…
severity: none
vendor: Linux
product: Linux
affected:
  - >-
    Linux >= a081c13e39b5c17052a7b46fafa61019c4c110ff <
    79991b770fc3685b1d5cf805b659a879edd19931
  - >-
    Linux >= a081c13e39b5c17052a7b46fafa61019c4c110ff <
    8db1232945bc663fb94f300090a1fc108de99296
  - >-
    Linux >= a081c13e39b5c17052a7b46fafa61019c4c110ff <
    94e5bdd08e51c450d954bc592f591c233ca5c9df
  - >-
    Linux >= a081c13e39b5c17052a7b46fafa61019c4c110ff <
    de96dc11aee0d058927bff94a168e3c5c46483e2
  - >-
    Linux >= a081c13e39b5c17052a7b46fafa61019c4c110ff <
    e3b25bf2cf2496e85bc05b33360faf9fdf880e03
  - >-
    Linux >= a081c13e39b5c17052a7b46fafa61019c4c110ff <
    ee56b5e18f566c0b5a183379dcd63d402cebf2f8
  - >-
    Linux >= a081c13e39b5c17052a7b46fafa61019c4c110ff <
    24ffc919467d20951f0f132d1c75294e2e91e09b
  - >-
    Linux >= a081c13e39b5c17052a7b46fafa61019c4c110ff <
    bce07e2f37b5e4a427d36fd6b1c14067b27591db
  - Linux 2.6.29
published: '2026-10-18'
updated: '2026-10-18'
sourceUpdated: '2026-10-18T15:15:53.663Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-98479'
references:
  - url: 'https://git.kernel.org/stable/c/79991b770fc3685b1d5cf805b659a879edd19931'
  - url: 'https://git.kernel.org/stable/c/8db1232945bc663fb94f300090a1fc108de99296'
  - url: 'https://git.kernel.org/stable/c/94e5bdd08e51c450d954bc592f591c233ca5c9df'
  - url: 'https://git.kernel.org/stable/c/de96dc11aee0d058927bff94a168e3c5c46483e2'
  - url: 'https://git.kernel.org/stable/c/e3b25bf2cf2496e85bc05b33360faf9fdf880e03'
  - url: 'https://git.kernel.org/stable/c/ee56b5e18f566c0b5a183379dcd63d402cebf2f8'
  - url: 'https://git.kernel.org/stable/c/24ffc919467d20951f0f132d1c75294e2e91e09b'
  - url: 'https://git.kernel.org/stable/c/bce07e2f37b5e4a427d36fd6b1c14067b27591db'
tags:
  - cve.org
ingestedAt: '2026-10-18T15:45:12.295Z'
---

## Overview

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

scsi: libiscsi_tcp: Check the data direction of a Data-In PDU

The Data-In branch of iscsi_tcp_hdr_dissect() resolves the ITT to a task
and copies the PDU's data segment into that command's scatterlist without
asking whether the command was reading. iscsi_tcp_r2t_rsp() in the same
file does ask, and rejects an R2T for a command that is not DMA_TO_DEVICE.

A target that answers a WRITE command's ITT with a Data-In therefore has
the initiator write target-supplied bytes into the pages that write was
about to send. Those are the caller's own pinned pages for an O_DIRECT
write, and page cache pages for a buffered one.

Observed against a test target that emits one 512-byte Data-In naming a 128
KB write's ITT, after the R2T for that write. With O_DIRECT the caller's
buffer ends up holding 512 bytes of the target's data while pwrite()
returns 131072. Buffered is quieter: pwrite() and fsync() both succeed,
nothing is logged, and reading those blocks back returns the target's bytes
out of the page cache without a command going on the wire.

Check the direction before using the scatterlist, the way the R2T path
already does.

## Affected

- `Linux >= a081c13e39b5c17052a7b46fafa61019c4c110ff < 79991b770fc3685b1d5cf805b659a879edd19931`
- `Linux >= a081c13e39b5c17052a7b46fafa61019c4c110ff < 8db1232945bc663fb94f300090a1fc108de99296`
- `Linux >= a081c13e39b5c17052a7b46fafa61019c4c110ff < 94e5bdd08e51c450d954bc592f591c233ca5c9df`
- `Linux >= a081c13e39b5c17052a7b46fafa61019c4c110ff < de96dc11aee0d058927bff94a168e3c5c46483e2`
- `Linux >= a081c13e39b5c17052a7b46fafa61019c4c110ff < e3b25bf2cf2496e85bc05b33360faf9fdf880e03`
- `Linux >= a081c13e39b5c17052a7b46fafa61019c4c110ff < ee56b5e18f566c0b5a183379dcd63d402cebf2f8`
- `Linux >= a081c13e39b5c17052a7b46fafa61019c4c110ff < 24ffc919467d20951f0f132d1c75294e2e91e09b`
- `Linux >= a081c13e39b5c17052a7b46fafa61019c4c110ff < bce07e2f37b5e4a427d36fd6b1c14067b27591db`
- `Linux 2.6.29`

## Remediation

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