# CVE-2023-53376: scsi: mpi3mr: Use number of bits to manage bitmap sizes

> A memory corruption vulnerability in the Linux kernel mpi3mr driver allows attackers to cause a denial of service via out-of-bounds access during firmware download.

- **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:** 18 Sep 2025
- **Updated:** 5 Aug 2026
- **Also known as:** AZL-72325, BELL-CVE-2023-53376, DEBIAN-CVE-2023-53376, GHSA-6f3q-hg2c-hwrx, ROOT-OS-UBUNTU-2204-CVE-2023-53376, UBUNTU-CVE-2023-53376

## What is CVE-2023-53376?

CVE-2023-53376 is a high-severity memory corruption vulnerability in Linux kernel, published on 18 Sep 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:

scsi: mpi3mr: Use number of bits to manage bitmap sizes

To allocate bitmaps, the mpi3mr driver calculates sizes of bitmaps using
byte as unit. However, bitmap helper functions assume that bitmaps are
allocated using unsigned long as unit. This gap causes memory access beyond
the bitmap sizes and results in "BUG: KASAN: slab-out-of-bounds".  The BUG
was observed at firmware download to eHBA-9600. Call trace indicated that
the out-of-bounds access happened in find_first_zero_bit() called from
mpi3mr_send_event_ack() for miroc->evtack_cmds_bitmap.

To fix the BUG, do not use bytes to manage bitmap sizes. Instead, use
number of bits, and call bitmap helper functions which take number of bits
as arguments. For memory allocation, call bitmap_zalloc() instead of
kzalloc() and krealloc(). For memory free, call bitmap_free() instead of
kfree(). For zero clear, call bitmap_clear() instead of memset().

Remove three fields for bitmap byte sizes in struct scmd_priv which are no
longer required. Replace the field dev_handle_bitmap_sz with
dev_handle_bitmap_bits to keep number of bits of removepend_bitmap across
resize.

Weakness: CWE-125 (Out-of-bounds Read)

## Which versions are affected by CVE-2023-53376?

It affects 1 product.


Products: Linux kernel.

## How do I fix CVE-2023-53376?

Apply the vendor's patch.

## Is CVE-2023-53376 being exploited?

There is no known exploitation of CVE-2023-53376 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-2023-53376 and fix it if it is affected.

What it is: CVE-2023-53376 is a high-severity memory corruption vulnerability in Linux kernel, published on 18 Sep 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-2023-53376 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-2023-53376/ (Markdown: https://insights.sbomify.com/CVE-2023-53376/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2023-53376
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2023-53376
- OSV: https://osv.dev/vulnerability/CVE-2023-53376

---
From sbomify Insights: https://insights.sbomify.com/CVE-2023-53376/
Summaries are generated and may contain mistakes; the official description above is the record.