# CVE-2026-53319: blk-wbt: remove WARN_ON_ONCE from wbt_init_enable_default()

> A spurious kernel warning triggered by memory allocation failures during block device initialization can cause system instability or denial of service.

- **Severity:** Medium 5.5 (`CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/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 Jun 2026
- **Updated:** 26 Jun 2026
- **Also known as:** DEBIAN-CVE-2026-53319, GHSA-8mp9-p9g8-5rm9, UBUNTU-CVE-2026-53319

## What is CVE-2026-53319?

CVE-2026-53319 is a medium-severity denial of service vulnerability in Linux kernel, published on 26 Jun 2026. 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:

blk-wbt: remove WARN_ON_ONCE from wbt_init_enable_default()

wbt_init_enable_default() uses WARN_ON_ONCE to check for failures from
wbt_alloc() and wbt_init(). However, both are expected failure paths:

- wbt_alloc() can return NULL under memory pressure (-ENOMEM)
- wbt_init() can fail with -EBUSY if wbt is already registered

syzbot triggers this by injecting memory allocation failures during MTD
partition creation via ioctl(BLKPG), causing a spurious warning.

wbt_init_enable_default() is a best-effort initialization called from
blk_register_queue() with a void return type. Failure simply means the
disk operates without writeback throttling, which is harmless.

Replace WARN_ON_ONCE with plain if-checks, consistent with how
wbt_set_lat() in the same file already handles these failures. Add a
pr_warn() for the wbt_init() failure to retain diagnostic information
without triggering a full stack trace.

Weakness: CWE-617 (Reachable Assertion)

## Which versions are affected by CVE-2026-53319?

It affects 1 product.


Products: Linux kernel.

## How do I fix CVE-2026-53319?

Apply the vendor's patch.

## Is CVE-2026-53319 being exploited?

There is no known exploitation of CVE-2026-53319 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-2026-53319 and fix it if it is affected.

What it is: CVE-2026-53319 is a medium-severity denial of service vulnerability in Linux kernel, published on 26 Jun 2026. 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-2026-53319 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-2026-53319/ (Markdown: https://insights.sbomify.com/CVE-2026-53319/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-53319
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-53319
- OSV: https://osv.dev/vulnerability/CVE-2026-53319

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-53319/
Summaries are generated and may contain mistakes; the official description above is the record.