# CVE-2025-40118: scsi: pm80xx: Fix array-index-out-of-of-bounds on rmmod

> A local attacker with root privileges can trigger a kernel crash by removing the pm80xx driver when an expander is connected.

- **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:** 12 Nov 2025
- **Updated:** 5 Aug 2026
- **Also known as:** BELL-CVE-2025-40118, DEBIAN-CVE-2025-40118, GHSA-fwp3-pc57-cmgf, ROOT-OS-DEBIAN-11-CVE-2025-40118, ROOT-OS-DEBIAN-13-CVE-2025-40118, UBUNTU-CVE-2025-40118

## What is CVE-2025-40118?

CVE-2025-40118 is a high-severity vulnerability in Linux, published on 12 Nov 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: pm80xx: Fix array-index-out-of-of-bounds on rmmod

Since commit f7b705c238d1 ("scsi: pm80xx: Set phy_attached to zero when
device is gone") UBSAN reports:

  UBSAN: array-index-out-of-bounds in drivers/scsi/pm8001/pm8001_sas.c:786:17
  index 28 is out of range for type 'pm8001_phy [16]'

on rmmod when using an expander.

For a direct attached device, attached_phy contains the local phy id.
For a device behind an expander, attached_phy contains the remote phy
id, not the local phy id.

I.e. while pm8001_ha will have pm8001_ha->chip->n_phy local phys, for a
device behind an expander, attached_phy can be much larger than
pm8001_ha->chip->n_phy (depending on the amount of phys of the
expander).

E.g. on my system pm8001_ha has 8 phys with phy ids 0-7.  One of the
ports has an expander connected.  The expander has 31 phys with phy ids
0-30.

The pm8001_ha->phy array only contains the phys of the HBA.  It does not
contain the phys of the expander.  Thus, it is wrong to use attached_phy
to index the pm8001_ha->phy array for a device behind an expander.

Thus, we can only clear phy_attached for devices that are directly
attached.

## Which versions are affected by CVE-2025-40118?


## How do I fix CVE-2025-40118?

Apply the vendor's patch.

## Is CVE-2025-40118 being exploited?

There is no known exploitation of CVE-2025-40118 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2025-40118 and fix it if it is affected.

What it is: CVE-2025-40118 is a high-severity vulnerability in Linux, published on 12 Nov 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-2025-40118 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-2025-40118/ (Markdown: https://insights.sbomify.com/CVE-2025-40118/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2025-40118
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2025-40118
- OSV: https://osv.dev/vulnerability/CVE-2025-40118

---
From sbomify Insights: https://insights.sbomify.com/CVE-2025-40118/
Summaries are generated and may contain mistakes; the official description above is the record.