# CVE-2023-52811: scsi: ibmvfc: Remove BUG_ON in the case of an empty event pool

> A missing null check in the ibmvfc driver can cause a kernel crash when the event pool is empty, leading to 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:** 21 May 2024
- **Updated:** 11 May 2026
- **Also known as:** BELL-CVE-2023-52811, DEBIAN-CVE-2023-52811, GHSA-j7xm-pf76-qww8, ROOT-OS-DEBIAN-11-CVE-2023-52811, UBUNTU-CVE-2023-52811

## What is CVE-2023-52811?

CVE-2023-52811 is a medium-severity vulnerability in Linux kernel, published on 21 May 2024. 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:

scsi: ibmvfc: Remove BUG_ON in the case of an empty event pool

In practice the driver should never send more commands than are allocated
to a queue's event pool. In the unlikely event that this happens, the code
asserts a BUG_ON, and in the case that the kernel is not configured to
crash on panic returns a junk event pointer from the empty event list
causing things to spiral from there. This BUG_ON is a historical artifact
of the ibmvfc driver first being upstreamed, and it is well known now that
the use of BUG_ON is bad practice except in the most unrecoverable
scenario. There is nothing about this scenario that prevents the driver
from recovering and carrying on.

Remove the BUG_ON in question from ibmvfc_get_event() and return a NULL
pointer in the case of an empty event pool. Update all call sites to
ibmvfc_get_event() to check for a NULL pointer and perfrom the appropriate
failure or recovery action.

Weakness: CWE-476 (NULL Pointer Dereference)

## Which versions are affected by CVE-2023-52811?

It affects 1 product.


Products: Linux kernel.

## How do I fix CVE-2023-52811?

Apply the vendor's patch.

## Is CVE-2023-52811 being exploited?

There is no known exploitation of CVE-2023-52811 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-2023-52811 and fix it if it is affected.

What it is: CVE-2023-52811 is a medium-severity vulnerability in Linux kernel, published on 21 May 2024. 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-2023-52811 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-2023-52811/ (Markdown: https://insights.sbomify.com/CVE-2023-52811/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2023-52811
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2023-52811
- OSV: https://osv.dev/vulnerability/CVE-2023-52811

---
From sbomify Insights: https://insights.sbomify.com/CVE-2023-52811/
Summaries are generated and may contain mistakes; the official description above is the record.