rapidio: mport_cdev: fix use-after-free in dma_req_free() (CVE-2026-89742) | HOL Guard CVE

Unknown severity · Source severity not reportedCVE-2026-89742

rapidio: mport_cdev: fix use-after-free in dma_req_free()

Answer in brief

CVE-2026-89742 records a Unknown severity vulnerability in rapidio: mport_cdev: fix use-after-free in dma_req_free(). The current sources do not mark it as known exploited. The current feed maps Linux/Linux (generic), Linux/Linux (generic). Check affected ranges and fixed versions before updating.

Analysis pending evidence review

HOL Guard separates source facts from reviewed analysis. See the methodology.

Published Sep 11, 2026Updated Sep 11, 2026Source checked Sep 11, 2026First seen by HOL Sep 11, 2026Material review Sep 11, 2026

Upstream Advisory

Key facts

Risk: Unknown severitySource severity not reported
Exploitation: Not marked as known exploited
Affected software: 2 mapped packages or products
Fix availability: Available

Why this deserves its current priority

A CVSS score is not reported in the current record. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.

Analysis status

Analysis pending evidence review

Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.

Affected scope and exposure questions

The current feed maps Linux/Linux (generic), Linux/Linux (generic). Check affected ranges and fixed versions before updating.

Mapped affected packages and fixed versions
Package	Affected range	Fixed version
Linux/Linuxgeneric	>=e8de370188d098bb49483c287b44925957c3c9b6 <9a9929ec875ff20922c90c96fd544ae8a2a61a8d \|\| >=e8de370188d098bb49483c287b44925957c3c9b6 <e6e925cc1f8067c65c7bec3da50a0ead3b3ef4e0 \|\| >=e8de370188d098bb49483c287b44925957c3c9b6 <211c68d817a3d9dc14c0026a59da7cac30f8147e \|\| >=e8de370188d098bb49483c287b44925957c3c9b6 <5cbef379a94b161726c5f504598bf4791d45cedc	9a9929ec875ff20922c90c96fd544ae8a2a61a8d, e6e925cc1f8067c65c7bec3da50a0ead3b3ef4e0, 211c68d817a3d9dc14c0026a59da7cac30f8147e, 5cbef379a94b161726c5f504598bf4791d45cedc
Linux/Linuxgeneric	4.6	Not reported

Recommended response

Check inventory. Check lockfiles and deployed manifests for Linux/Linux, Linux/Linux.
Review the reported fix. Update Linux/Linux to 9a9929ec875ff20922c90c96fd544ae8a2a61a8d if you use the affected versions. Test the change in a non-production environment first.

Evidence timeline and material changes

Published upstream
Sep 11, 2026
Evidence: source:cvelist:source_dates:source-dates:record
Source modified
Sep 11, 2026
Evidence: source:cvelist:source_dates:source-dates:record
First seen by HOL
Sep 11, 2026

Sources and claim methodology

Upstream source 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.

Quoted source text, attributed separately from HOL analysis.