# CVE-2023-54227: blk-mq: fix tags leak when shrink nr_hw_queues

> A memory leak in the Linux kernel block layer allows local attackers to exhaust system memory, potentially causing a denial of service.

- **Severity:** High 7.5 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 30 Dec 2025
- **Updated:** 15 Oct 2026
- **Also known as:** BELL-CVE-2023-54227, DEBIAN-CVE-2023-54227, GHSA-5vch-5hxh-2rq8, ROOT-OS-DEBIAN-12-CVE-2023-54227, ROOT-OS-UBUNTU-2204-CVE-2023-54227, UBUNTU-CVE-2023-54227

## What is CVE-2023-54227?

CVE-2023-54227 is a high-severity denial of service vulnerability in Linux, published on 30 Dec 2025. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

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

blk-mq: fix tags leak when shrink nr_hw_queues

Although we don't need to realloc set->tags[] when shrink nr_hw_queues,
we need to free them. Or these tags will be leaked.

How to reproduce:
1. mount -t configfs configfs /mnt
2. modprobe null_blk nr_devices=0 submit_queues=8
3. mkdir /mnt/nullb/nullb0
4. echo 1 > /mnt/nullb/nullb0/power
5. echo 4 > /mnt/nullb/nullb0/submit_queues
6. rmdir /mnt/nullb/nullb0

In step 4, will alloc 9 tags (8 submit queues and 1 poll queue), then
in step 5, new_nr_hw_queues = 5 (4 submit queues and 1 poll queue).
At last in step 6, only these 5 tags are freed, the other 4 tags leaked.

## Which versions are affected by CVE-2023-54227?


## How do I fix CVE-2023-54227?

Apply the vendor's patch.

## Is CVE-2023-54227 being exploited?

There is no known exploitation of CVE-2023-54227 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2023-54227 and fix it if it is affected.

What it is: CVE-2023-54227 is a high-severity denial of service vulnerability in Linux, published on 30 Dec 2025. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2023-54227 in the wild and no public exploit code.

Affected product: Linux. 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-2023-54227/ (Markdown: https://insights.sbomify.com/CVE-2023-54227/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2023-54227
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2023-54227
- OSV: https://osv.dev/vulnerability/CVE-2023-54227

---
From sbomify Insights: https://insights.sbomify.com/CVE-2023-54227/
Summaries are generated and may contain mistakes; the official description above is the record.