---
id: CVE-2026-64259
title: |-
  In the Linux kernel, the following vulnerability has been resolved:

  fuse-uring: make a fuse_req on SQE commit only findable after memcpy

  Bad userspace might try to trick us and send commit SQEs request
  unique / commit-id of requests th…
summary: |-
  In the Linux kernel, the following vulnerability has been resolved:

  fuse-uring: make a fuse_req on SQE commit only findable after memcpy

  Bad userspace might try to trick us and send commit SQEs request
  unique / commit-id of requests th…
severity: high
cvss: 7.8
cvssVector: 'CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H'
published: '2026-07-25'
updated: '2026-07-27'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-64259'
references:
  - url: 'https://git.kernel.org/stable/c/1efd3d474fc0ba74dfd984249bca78807d739812'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/a635f427d57e2012102ae4886b48d8955c59fb86'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
  - url: 'https://git.kernel.org/stable/c/e1711479e9068ea31b31353a702a51e639c3d059'
    label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
tags:
  - nvd
epss: 0.00157
epssPercentile: 0.05277
ingestedAt: '2026-07-27T06:16:49.591Z'
---

## Overview

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

fuse-uring: make a fuse_req on SQE commit only findable after memcpy

Bad userspace might try to trick us and send commit SQEs request
unique / commit-id of requests that are not even send to
fuse-server (io_uring_cmd_done() not called) yet.

fuse_uring_commit_fetch() ends the fuse request when the ring entry
has a wrong state, but that could have caused a use-after-free
with the memcpy operations in fuse_uring_send_in_task().
In order to avoid such races the call of fuse_uring_add_to_pq()
is moved after the copy operations and just before completing
the io-uring request - malicious userspace cannot find the request
anymore until all prepration work in fuse-client/kernel is completed.

This also moves fuse_uring_add_to_pq() a bit up in the code to
avoid a forward declaration. Also not with a preparation commit,
to make it easier to back port to older kernels.

## Remediation

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