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CVE-2026-89742

7.8 · HIGH

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…

Published Sep 11, 2026EPSS 0.16%

Overview

CVE-2026-89742 is a high-severity vulnerability. It was published on September 11, 2026 and has a CVSS 3.1 base score of 7.8 (HIGH).

This vulnerability has a CVSS 3.1 base score of 7.8, rated HIGH. It requires local or adjacent network access to exploit. Some level of privileges is required for exploitation.

Technical description

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.

Remediation

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

References

Refgit.kernel.org/stable/c/00c5ed913b0dc563fbeb8a97ea8916c03bbbbf6aRefgit.kernel.org/stable/c/211c68d817a3d9dc14c0026a59da7cac30f8147eRefgit.kernel.org/stable/c/26ccfe7d69e27b0d933ae0a64a23a0cb9b9a85a6Refgit.kernel.org/stable/c/5cbef379a94b161726c5f504598bf4791d45cedcRefgit.kernel.org/stable/c/9a9929ec875ff20922c90c96fd544ae8a2a61a8dRefgit.kernel.org/stable/c/bd8881c24a9520f9c3d3e855d866197f63e471a7Refgit.kernel.org/stable/c/e6e925cc1f8067c65c7bec3da50a0ead3b3ef4e0Refgit.kernel.org/stable/c/fc79c07cdcde02c5b17633d78777de6ac2c14b29

How CyberStrike helps

Frequently asked questions

What is CVE-2026-89742?

CVE-2026-89742 is a high-severity vulnerability. It was published on September 11, 2026 and has a CVSS 3.1 base score of 7.8 (HIGH).

How severe is CVE-2026-89742?

This vulnerability has a CVSS 3.1 base score of 7.8, rated HIGH. It requires local or adjacent network access to exploit. Some level of privileges is required for exploitation.

How do I fix or remediate CVE-2026-89742?

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

How can CyberStrike help with CVE-2026-89742?

CyberStrike is an open-source, AI-augmented pentesting engine. Rather than flag a version number, it tests whether an issue like CVE-2026-89742 is actually reachable in your own applications and APIs, then verifies each finding before reporting it. That tells you if the weakness is a real, exploitable risk in your environment or a false positive you can safely deprioritize.

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