# CVE-2022-49176: bfq: fix use-after-free in bfq_dispatch_request

> A use-after-free vulnerability in the Linux kernel's BFQ I/O scheduler allows attackers to cause denial of service or potentially execute code.

- **Severity:** High 7.8 (`CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 26 Feb 2025
- **Updated:** 12 Aug 2026
- **Also known as:** DEBIAN-CVE-2022-49176, GHSA-95jr-p4jm-v55x, UBUNTU-CVE-2022-49176

## What is CVE-2022-49176?

CVE-2022-49176 is a high-severity use after free vulnerability in Linux kernel, published on 26 Feb 2025. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

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

bfq: fix use-after-free in bfq_dispatch_request

KASAN reports a use-after-free report when doing normal scsi-mq test

[69832.239032] ==================================================================
[69832.241810] BUG: KASAN: use-after-free in bfq_dispatch_request+0x1045/0x44b0
[69832.243267] Read of size 8 at addr ffff88802622ba88 by task kworker/3:1H/155
[69832.244656]
[69832.245007] CPU: 3 PID: 155 Comm: kworker/3:1H Not tainted 5.10.0-10295-g576c6382529e #8
[69832.246626] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.14.0-0-g155821a1990b-prebuilt.qemu.org 04/01/2014
[69832.249069] Workqueue: kblockd blk_mq_run_work_fn
[69832.250022] Call Trace:
[69832.250541]  dump_stack+0x9b/0xce
[69832.251232]  ? bfq_dispatch_request+0x1045/0x44b0
[69832.252243]  print_address_description.constprop.6+0x3e/0x60
[69832.253381]  ? __cpuidle_text_end+0x5/0x5
[69832.254211]  ? vprintk_func+0x6b/0x120
[69832.254994]  ? bfq_dispatch_request+0x1045/0x44b0
[69832.255952]  ? bfq_dispatch_request+0x1045/0x44b0
[69832.256914]  kasan_report.cold.9+0x22/0x3a
[69832.257753]  ? bfq_dispatch_request+0x1045/0x44b0
[69832.258755]  check_memory_region+0x1c1/0x1e0
[69832.260248]  bfq_dispatch_request+0x1045/0x44b0
[69832.261181]  ? bfq_bfqq_expire+0x2440/0x2440
[69832.262032]  ? blk_mq_delay_run_hw_queues+0xf9/0x170
[69832.263022]  __blk_mq_do_dispatch_sched+0x52f/0x830
[69832.264011]  ? blk_mq_sched_request_inserted+0x100/0x100
[69832.265101]  __blk_mq_sched_dispatch_requests+0x398/0x4f0
[69832.266206]  ? blk_mq_do_dispatch_ctx+0x570/0x570
[69832.267147]  ? __switch_to+0x5f4/0xee0
[69832.267898]  blk_mq_sched_dispatch_requests+0xdf/0x140
[69832.268946]  __blk_mq_run_hw_queue+0xc0/0x270
[69832.269840]  blk_mq_run_work_fn+0x51/0x60
[69832.278170]  process_one_work+0x6d4/0xfe0
[69832.278984]  worker_thread+0x91/0xc80
[69832.279726]  ? __kthread_parkme+0xb0/0x110
[69832.280554]  ? process_one_work+0xfe0/0xfe0
[69832.281414]  kthread+0x32d/0x3f0
[69832.282082]  ? kthread_park+0x170/0x170
[69832.282849]  ret_from_fork+0x1f/0x30
[69832.283573]
[69832.283886] Allocated by task 7725:
[69832.284599]  kasan_save_stack+0x19/0x40
[69832.285385]  __kasan_kmalloc.constprop.2+0xc1/0xd0
[69832.286350]  kmem_cache_alloc_node+0x13f/0x460
[69832.287237]  bfq_get_queue+0x3d4/0x1140
[69832.287993]  bfq_get_bfqq_handle_split+0x103/0x510
[69832.289015]  bfq_init_rq+0x337/0x2d50
[69832.289749]  bfq_insert_requests+0x304/0x4e10
[69832.290634]  blk_mq_sched_insert_requests+0x13e/0x390
[69832.291629]  blk_mq_flush_plug_list+0x4b4/0x760
[69832.292538]  blk_flush_plug_list+0x2c5/0x480
[69832.293392]  io_schedule_prepare+0xb2/0xd0
[69832.294209]  io_schedule_timeout+0x13/0x80
[69832.295014]  wait_for_common_io.constprop.1+0x13c/0x270
[69832.296137]  submit_bio_wait+0x103/0x1a0
[69832.296932]  blkdev_issue_discard+0xe6/0x160
[69832.297794]  blk_ioctl_discard+0x219/0x290
[69832.298614]  blkdev_common_ioctl+0x50a/0x1750
[69832.304715]  blkdev_ioctl+0x470/0x600
[69832.305474]  block_ioctl+0xde/0x120
[69832.306232]  vfs_ioctl+0x6c/0xc0
[69832.306877]  __se_sys_ioctl+0x90/0xa0
[69832.307629]  do_syscall_64+0x2d/0x40
[69832.308362]  entry_SYSCALL_64_after_hwframe+0x44/0xa9
[69832.309382]
[69832.309701] Freed by task 155:
[69832.310328]  kasan_save_stack+0x19/0x40
[69832.311121]  kasan_set_track+0x1c/0x30
[69832.311868]  kasan_set_free_info+0x1b/0x30
[69832.312699]  __kasan_slab_free+0x111/0x160
[69832.313524]  kmem_cache_free+0x94/0x460
[69832.314367]  bfq_put_queue+0x582/0x940
[69832.315112]  __bfq_bfqd_reset_in_service+0x166/0x1d0
[69832.317275]  bfq_bfqq_expire+0xb27/0x2440
[69832.318084]  bfq_dispatch_request+0x697/0x44b0
[69832.318991]  __blk_mq_do_dispatch_sched+0x52f/0x830
[69832.319984]  __blk_mq_sched_dispatch_requests+0x398/0x4f0
[69832.321087]  blk_mq_sched_dispatch_requests+0xdf/0x140
[69832.322225]  __blk_mq_run_hw_queue+0xc0/0x270
[69832.323114]  blk_mq_run_work_fn+0x51/0x6
---truncated---

Weakness: CWE-416 (Use After Free)

## Which versions are affected by CVE-2022-49176?

It affects 1 product.


Products: Linux kernel.

## How do I fix CVE-2022-49176?

Apply the vendor's patch.

## Is CVE-2022-49176 being exploited?

There is no known exploitation of CVE-2022-49176 in the wild and no public exploit code.

## Other vulnerabilities in Linux kernel

- [CVE-2026-53266](https://insights.sbomify.com/CVE-2026-53266/): Linux Kernel Out-of-Bounds Write (high 8.8, exploited in the wild)
- [CVE-2013-6282](https://insights.sbomify.com/CVE-2013-6282/): Linux Kernel Improper Input Validation (high 8.8, exploited in the wild)
- [CVE-2022-0185](https://insights.sbomify.com/CVE-2022-0185/): Linux Kernel Heap-Based Buffer Overflow (high 8.4, exploited in the wild)
- [CVE-2013-2094](https://insights.sbomify.com/CVE-2013-2094/): Linux Kernel Privilege Escalation (high 8.4, exploited in the wild)
- [CVE-2026-53362](https://insights.sbomify.com/CVE-2026-53362/): Linux Kernel Unspecified (high 7.8, exploited in the wild)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2022-49176 and fix it if it is affected.

What it is: CVE-2022-49176 is a high-severity use after free vulnerability in Linux kernel, published on 26 Feb 2025. It can only be exploited from the same machine or local network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2022-49176 in the wild and no public exploit code.

Affected product: Linux kernel. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2022-49176/ (Markdown: https://insights.sbomify.com/CVE-2022-49176/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2022-49176
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2022-49176
- OSV: https://osv.dev/vulnerability/CVE-2022-49176

---
From sbomify Insights: https://insights.sbomify.com/CVE-2022-49176/
Summaries are generated and may contain mistakes; the official description above is the record.