---
id: CVE-2026-89742
title: >-
  kernel: rapidio: mport_cdev: fix use-after-free in dma_req_free()
  (CVE-2026-89742)
summary: >-
  A flaw was found in the Linux kernel. A local user could exploit a
  use-after-free vulnerability in the `dma_req_free()` function within the
  RapidIO mport character device interface. This flaw occurs when the
  `dma_req_free()` function attem…
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'
cvssSource: vendor
cwe: CWE-825
vendor: Red Hat
product: Linux
affected:
  - >-
    Linux >= e8de370188d098bb49483c287b44925957c3c9b6 <
    00c5ed913b0dc563fbeb8a97ea8916c03bbbbf6a
  - >-
    Linux >= e8de370188d098bb49483c287b44925957c3c9b6 <
    fc79c07cdcde02c5b17633d78777de6ac2c14b29
  - >-
    Linux >= e8de370188d098bb49483c287b44925957c3c9b6 <
    26ccfe7d69e27b0d933ae0a64a23a0cb9b9a85a6
  - >-
    Linux >= e8de370188d098bb49483c287b44925957c3c9b6 <
    bd8881c24a9520f9c3d3e855d866197f63e471a7
  - >-
    Linux >= e8de370188d098bb49483c287b44925957c3c9b6 <
    9a9929ec875ff20922c90c96fd544ae8a2a61a8d
  - >-
    Linux >= e8de370188d098bb49483c287b44925957c3c9b6 <
    e6e925cc1f8067c65c7bec3da50a0ead3b3ef4e0
  - >-
    Linux >= e8de370188d098bb49483c287b44925957c3c9b6 <
    211c68d817a3d9dc14c0026a59da7cac30f8147e
  - >-
    Linux >= e8de370188d098bb49483c287b44925957c3c9b6 <
    5cbef379a94b161726c5f504598bf4791d45cedc
  - Linux 4.6
published: '2026-09-11'
updated: '2026-09-21'
sourceUpdated: '2026-09-21T17:28:13+00:00'
source: CSAF
sourceUrl: 'https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-89742.json'
references:
  - url: >-
      https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-89742.json
  - url: 'https://access.redhat.com/security/cve/CVE-2026-89742'
  - url: 'https://bugzilla.redhat.com/show_bug.cgi?id=2532155'
  - url: 'https://www.cve.org/CVERecord?id=CVE-2026-89742'
  - url: 'https://nvd.nist.gov/vuln/detail/CVE-2026-89742'
  - url: >-
      https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-89742.mbox
  - url: 'https://git.kernel.org/stable/c/00c5ed913b0dc563fbeb8a97ea8916c03bbbbf6a'
  - url: 'https://git.kernel.org/stable/c/fc79c07cdcde02c5b17633d78777de6ac2c14b29'
  - url: 'https://git.kernel.org/stable/c/26ccfe7d69e27b0d933ae0a64a23a0cb9b9a85a6'
  - url: 'https://git.kernel.org/stable/c/bd8881c24a9520f9c3d3e855d866197f63e471a7'
  - url: 'https://git.kernel.org/stable/c/9a9929ec875ff20922c90c96fd544ae8a2a61a8d'
  - url: 'https://git.kernel.org/stable/c/e6e925cc1f8067c65c7bec3da50a0ead3b3ef4e0'
  - url: 'https://git.kernel.org/stable/c/211c68d817a3d9dc14c0026a59da7cac30f8147e'
  - url: 'https://git.kernel.org/stable/c/5cbef379a94b161726c5f504598bf4791d45cedc'
tags:
  - csaf
  - vex
  - red-hat
  - cve.org
  - score-dispute
epss: 0.00171
epssPercentile: 0.05736
scores:
  vendor: 5.5
  cna: 7.8
ingestedAt: '2026-09-14T15:23:07.449Z'
---

## Overview

A flaw was found in the Linux kernel. A local user could exploit a use-after-free vulnerability in the `dma_req_free()` function within the RapidIO mport character device interface. This flaw occurs when the `dma_req_free()` function attempts to dereference a freed object after dropping the last reference to a mapping. Successful exploitation of this vulnerability could lead to arbitrary code execution or a denial of service.

## Vendor advisories

- **Red Hat VEX** · Moderate · updated 2026-09-21 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-89742.json)

**kernel: rapidio: mport_cdev: fix use-after-free in dma_req_free()** — rated Moderate by Red Hat. Released 2026-09-11, updated 2026-09-21.

Not affected:

- Red Hat Enterprise Linux 10
- Red Hat Enterprise Linux 6
- Red Hat Enterprise Linux 7
- Red Hat Enterprise Linux 8
- Red Hat Enterprise Linux 9
- Red Hat OpenShift Container Platform 4

## Remediation

Refer to the advisory for fix availability.