---
id: CVE-2026-80811
title: 'io_uring/cmd: fix iovec leak when the async cmd is not recycled'
summary: |-
  In the Linux kernel, the following vulnerability has been resolved:

  io_uring/cmd: fix iovec leak when the async cmd is not recycled

  An io_async_cmd carries an iovec array in ->vec.iovec, allocated when the
  vec has to grow and kept acro…
severity: none
vendor: Linux
product: Linux
affected:
  - >-
    Linux >= 3a4689ac109f18f23ea0d0c1c79e055142796858 <
    b6a768aa975b9ca81b92f028bdd975d1f8237894
  - >-
    Linux >= 3a4689ac109f18f23ea0d0c1c79e055142796858 <
    b290de4d16d75b6c1ef42025b47f5d94eb1ec09f
  - >-
    Linux >= 3a4689ac109f18f23ea0d0c1c79e055142796858 <
    7068d3587a64a24943a7c9e232976da2c9e0e303
  - >-
    Linux >= 3a4689ac109f18f23ea0d0c1c79e055142796858 <
    bb34ae5da3365699d53a756f4c96b6ea9f8ba0c1
  - Linux 6.15
published: '2026-09-04'
updated: '2026-10-19'
sourceUpdated: '2026-10-19T08:44:04.686Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-80811'
references:
  - url: 'https://git.kernel.org/stable/c/b6a768aa975b9ca81b92f028bdd975d1f8237894'
  - url: 'https://git.kernel.org/stable/c/b290de4d16d75b6c1ef42025b47f5d94eb1ec09f'
  - url: 'https://git.kernel.org/stable/c/7068d3587a64a24943a7c9e232976da2c9e0e303'
  - url: 'https://git.kernel.org/stable/c/bb34ae5da3365699d53a756f4c96b6ea9f8ba0c1'
tags:
  - cve.org
epss: 0.00209
epssPercentile: 0.10306
ingestedAt: '2026-10-19T09:16:01.508Z'
---

## Overview

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

io_uring/cmd: fix iovec leak when the async cmd is not recycled

An io_async_cmd carries an iovec array in ->vec.iovec, allocated when the
vec has to grow and kept across recycling through ctx->cmd_cache.  On two
paths nothing frees it and io_clean_op()'s kfree(req->async_data) drops
the io_async_cmd without it.

io_req_uring_cleanup() clears the async data flags only when
io_alloc_cache_put() succeeds, and the cache holds IO_ALLOC_CACHE_MAX ==
128 entries, so once it is full the put fails and the vec is left behind.
An NVMe passthrough workload gets there without doing anything unusual:
nvme_uring_cmd_io() returns -EIOCBQUEUED, so the io_async_cmd stays
attached for the lifetime of the command and the live object count tracks
the queue depth.  Above 128 the puts start failing.

->cleanup is the last chance to free an inherited vec, since
io_req_uring_cleanup() returns early for an io-wq issued command and is
not called at all for one completed without ever being issued.  But
io_clean_op() calls ->cleanup only if REQ_F_NEED_CLEANUP is set, and for
uring_cmd that happens only where the vec has to grow, so a command
reusing a large enough cached vec never sets it.  io_rw_alloc_async() and
io_msg_alloc_async() flag an inherited vec for exactly this reason;
io_uring_cmd_prep() does not.

Flag an inherited vec in io_uring_cmd_prep(), and free the vec when the
cache put fails, as io_req_rw_cleanup() does.

The leak is invisible under KASAN, where io_alloc_cache_vec_kasan() frees
the vec unconditionally.

## Affected

- `Linux >= 3a4689ac109f18f23ea0d0c1c79e055142796858 < b6a768aa975b9ca81b92f028bdd975d1f8237894`
- `Linux >= 3a4689ac109f18f23ea0d0c1c79e055142796858 < b290de4d16d75b6c1ef42025b47f5d94eb1ec09f`
- `Linux >= 3a4689ac109f18f23ea0d0c1c79e055142796858 < 7068d3587a64a24943a7c9e232976da2c9e0e303`
- `Linux >= 3a4689ac109f18f23ea0d0c1c79e055142796858 < bb34ae5da3365699d53a756f4c96b6ea9f8ba0c1`
- `Linux 6.15`

## Remediation

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