Copyright © 2012 Red Hat, Inc. All rights reserved. Moderate 2026-09-11T00:00:00 kernel: rapidio: mport_cdev: fix use-after-free in dma_req_free() 5.5 CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H CWE-825

In the Linux kernel, the following vulnerability has been resolved: rapidio: mport_cdev: fix use-after-free in dma_req_free() dma_req_free() acquires buf_mutex through req->map, drops the mapping reference with kref_put(), and then dereferences req->map again to unlock the mutex. If kref_put() drops the last reference, mport_release_mapping() frees the mapping, and the subsequent mutex_unlock() dereferences a freed object. This is a use-after-free. Fix this by caching map and md before kref_put(), clearing req->map while holding buf_mutex, and using the cached md for mutex unlocking. The bug is reachable from userspace via the RapidIO mport character device interface.

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.

Red Hat Enterprise Linux 10 Not affected kernel Red Hat Enterprise Linux 10 Not affected kernel-rt Red Hat Enterprise Linux 6 Not affected kernel Red Hat Enterprise Linux 7 Not affected kernel Red Hat Enterprise Linux 7 Not affected kernel-rt Red Hat Enterprise Linux 8 Not affected kernel Red Hat Enterprise Linux 8 Not affected kernel-rt Red Hat Enterprise Linux 9 Not affected kernel Red Hat Enterprise Linux 9 Not affected kernel-rt Red Hat OpenShift Container Platform 4 Not affected openshift/ose-rhel-coreos-8 Red Hat OpenShift Container Platform 4 Not affected openshift/ose-rhel-coreos-9 https://www.cve.org/CVERecord?id=CVE-2026-89742 https://nvd.nist.gov/vuln/detail/CVE-2026-89742 https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-89742.mbox