# CVE-2025-39788: scsi: ufs: exynos: Fix programming of HCI_UTRL_NEXUS_TYPE

> An integer overflow in the Exynos UFS driver causes undefined behavior and potential denial of service on Google gs101 devices.

- **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:** 11 Sep 2025
- **Updated:** 12 May 2026
- **Also known as:** BELL-CVE-2025-39788, DEBIAN-CVE-2025-39788, GHSA-44fw-3x9p-jf29, ROOT-OS-DEBIAN-11-CVE-2025-39788, ROOT-OS-DEBIAN-12-CVE-2025-39788, ROOT-OS-DEBIAN-13-CVE-2025-39788, ROOT-OS-UBUNTU-2204-CVE-2025-39788, ROOT-OS-UBUNTU-2404-CVE-2025-39788, UBUNTU-CVE-2025-39788

## What is CVE-2025-39788?

CVE-2025-39788 is a high-severity vulnerability in Debian Debian Linux, published on 11 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: ufs: exynos: Fix programming of HCI_UTRL_NEXUS_TYPE

On Google gs101, the number of UTP transfer request slots (nutrs) is 32,
and in this case the driver ends up programming the UTRL_NEXUS_TYPE
incorrectly as 0.

This is because the left hand side of the shift is 1, which is of type
int, i.e. 31 bits wide. Shifting by more than that width results in
undefined behaviour.

Fix this by switching to the BIT() macro, which applies correct type
casting as required. This ensures the correct value is written to
UTRL_NEXUS_TYPE (0xffffffff on gs101), and it also fixes a UBSAN shift
warning:

    UBSAN: shift-out-of-bounds in drivers/ufs/host/ufs-exynos.c:1113:21
    shift exponent 32 is too large for 32-bit type 'int'

For consistency, apply the same change to the nutmrs / UTMRL_NEXUS_TYPE
write.

Weakness: CWE-787 (Out-of-bounds Write)

## Which versions are affected by CVE-2025-39788?

It affects 2 products.


Products: Debian Debian Linux, Linux kernel.

## How do I fix CVE-2025-39788?

Apply the vendor's patch.

## Is CVE-2025-39788 being exploited?

There is no known exploitation of CVE-2025-39788 in the wild and no public exploit code.

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- [CVE-2026-24061](https://insights.sbomify.com/CVE-2026-24061/): GNU InetUtils Argument Injection (critical 9.8, exploited in the wild)
- [CVE-2025-39682](https://insights.sbomify.com/CVE-2025-39682/): Linux Kernel Improper Check for Unusual or Exceptional Conditions (critical 9.8, exploited in the wild)
- [CVE-2024-9680](https://insights.sbomify.com/CVE-2024-9680/): Mozilla Firefox Use-After-Free (critical 9.8, exploited in the wild)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2025-39788 and fix it if it is affected.

What it is: CVE-2025-39788 is a high-severity vulnerability in Debian Debian Linux, published on 11 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-2025-39788 in the wild and no public exploit code.

Affected product: Debian Debian 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-2025-39788/ (Markdown: https://insights.sbomify.com/CVE-2025-39788/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2025-39788
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2025-39788
- OSV: https://osv.dev/vulnerability/CVE-2025-39788

---
From sbomify Insights: https://insights.sbomify.com/CVE-2025-39788/
Summaries are generated and may contain mistakes; the official description above is the record.