---
id: CVE-2026-74734
title: 'firewire: ohci: fix NULL pointer dereference in ar_context_release'
summary: |-
  In the Linux kernel, the following vulnerability has been resolved:

  firewire: ohci: fix NULL pointer dereference in ar_context_release

  During the error handling path of the driver's probe function, a NULL
  pointer dereference can occur …
severity: none
vendor: Linux
product: Linux
affected:
  - >-
    Linux >= 5716e58aecdd4f7225c2e46ce903a839fc54f22f <
    3770a4794a14331c8ca6a674e49c021827521c2c
  - >-
    Linux >= 5716e58aecdd4f7225c2e46ce903a839fc54f22f <
    ca2fa74f3200ced6e0a940753ad99844c42ad7c8
  - >-
    Linux >= 5716e58aecdd4f7225c2e46ce903a839fc54f22f <
    ed5470771c7ed7f959230c4697f316af83426a90
  - >-
    Linux >= 5716e58aecdd4f7225c2e46ce903a839fc54f22f <
    7d228ba43279de2d191f25e139fad166409c2c06
  - >-
    Linux >= 5716e58aecdd4f7225c2e46ce903a839fc54f22f <
    42d217add8d80d6e7d9f58f80d11ea9b07ea113e
  - Linux 6.5
published: '2026-08-26'
updated: '2026-10-21'
sourceUpdated: '2026-10-21T12:46:20.638Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-74734'
references:
  - url: 'https://git.kernel.org/stable/c/3770a4794a14331c8ca6a674e49c021827521c2c'
  - url: 'https://git.kernel.org/stable/c/ca2fa74f3200ced6e0a940753ad99844c42ad7c8'
  - url: 'https://git.kernel.org/stable/c/ed5470771c7ed7f959230c4697f316af83426a90'
  - url: 'https://git.kernel.org/stable/c/7d228ba43279de2d191f25e139fad166409c2c06'
  - url: 'https://git.kernel.org/stable/c/42d217add8d80d6e7d9f58f80d11ea9b07ea113e'
tags:
  - cve.org
epss: 0.00206
epssPercentile: 0.10131
ingestedAt: '2026-10-21T12:48:53.575Z'
---

## Overview

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

firewire: ohci: fix NULL pointer dereference in ar_context_release

During the error handling path of the driver's probe function, a NULL
pointer dereference can occur in ar_context_release().

When pci_probe() fails early (e.g., if pcim_enable_device() or MMIO mapping
fails), the devres cleanup mechanism invokes release_ohci(). This function
unconditionally calls ar_context_release() to clean up the asynchronous
receive contexts. However, if ar_context_init() was not yet called,
ctx->ohci remains NULL (as the fw_ohci structure is zero-initialized by
devres_alloc()).

ar_context_release() immediately dereferences ctx->ohci to get the dev
pointer before checking if the context was actually initialized, leading to
a crash:

Oops: general protection fault, probably for non-canonical address
0xdffffc0000000001: 0000 [#1] SMP KASAN NOPTI
KASAN: null-ptr-deref in range [0x0000000000000008-0x000000000000000f]
RIP: 0010:ar_context_release+0x3f/0x380 drivers/firewire/ohci.c:543
Call Trace:
 release_ohci+0x3f/0x60 drivers/firewire/ohci.c:3567
 release_nodes drivers/base/devres.c:546 [inline]
 devres_release_all+0x1a8/0x260 drivers/base/devres.c:576
 device_unbind_cleanup drivers/base/dd.c:597 [inline]
 really_probe+0x451/0xae0 drivers/base/dd.c:772

To fix this, move the assignment of the dev pointer after the !ctx->buffer
check. If ctx->buffer is NULL, it indicates that the context was never
successfully initialized and there is nothing to release, safely avoiding
the dereference of the uninitialized ctx->ohci pointer.

## Affected

- `Linux >= 5716e58aecdd4f7225c2e46ce903a839fc54f22f < 3770a4794a14331c8ca6a674e49c021827521c2c`
- `Linux >= 5716e58aecdd4f7225c2e46ce903a839fc54f22f < ca2fa74f3200ced6e0a940753ad99844c42ad7c8`
- `Linux >= 5716e58aecdd4f7225c2e46ce903a839fc54f22f < ed5470771c7ed7f959230c4697f316af83426a90`
- `Linux >= 5716e58aecdd4f7225c2e46ce903a839fc54f22f < 7d228ba43279de2d191f25e139fad166409c2c06`
- `Linux >= 5716e58aecdd4f7225c2e46ce903a839fc54f22f < 42d217add8d80d6e7d9f58f80d11ea9b07ea113e`
- `Linux 6.5`

## Remediation

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