# CVE-2022-49720: block: Fix handling of offline queues in blk_mq_alloc_request_hctx()

> A local attacker can trigger an out-of-bounds array index in the Linux kernel block layer, causing a system crash or denial of service.

- **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:** 11 May 2026
- **Also known as:** DEBIAN-CVE-2022-49720, GHSA-2vww-w979-x68j, UBUNTU-CVE-2022-49720

## What is CVE-2022-49720?

CVE-2022-49720 is a high-severity 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:

block: Fix handling of offline queues in blk_mq_alloc_request_hctx()

This patch prevents that test nvme/004 triggers the following:

UBSAN: array-index-out-of-bounds in block/blk-mq.h:135:9
index 512 is out of range for type 'long unsigned int [512]'
Call Trace:
 show_stack+0x52/0x58
 dump_stack_lvl+0x49/0x5e
 dump_stack+0x10/0x12
 ubsan_epilogue+0x9/0x3b
 __ubsan_handle_out_of_bounds.cold+0x44/0x49
 blk_mq_alloc_request_hctx+0x304/0x310
 __nvme_submit_sync_cmd+0x70/0x200 [nvme_core]
 nvmf_connect_io_queue+0x23e/0x2a0 [nvme_fabrics]
 nvme_loop_connect_io_queues+0x8d/0xb0 [nvme_loop]
 nvme_loop_create_ctrl+0x58e/0x7d0 [nvme_loop]
 nvmf_create_ctrl+0x1d7/0x4d0 [nvme_fabrics]
 nvmf_dev_write+0xae/0x111 [nvme_fabrics]
 vfs_write+0x144/0x560
 ksys_write+0xb7/0x140
 __x64_sys_write+0x42/0x50
 do_syscall_64+0x35/0x80
 entry_SYSCALL_64_after_hwframe+0x44/0xae

Weakness: CWE-129 (Improper Validation of Array Index)

## Which versions are affected by CVE-2022-49720?

It affects 1 product.


Products: Linux kernel.

## How do I fix CVE-2022-49720?

Apply the vendor's patch.

## Is CVE-2022-49720 being exploited?

There is no known exploitation of CVE-2022-49720 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-2022-49720 and fix it if it is affected.

What it is: CVE-2022-49720 is a high-severity 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-2022-49720 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-2022-49720/ (Markdown: https://insights.sbomify.com/CVE-2022-49720/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2022-49720
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2022-49720
- OSV: https://osv.dev/vulnerability/CVE-2022-49720

---
From sbomify Insights: https://insights.sbomify.com/CVE-2022-49720/
Summaries are generated and may contain mistakes; the official description above is the record.