# CVE-2025-39715: parisc: Revise gateway LWS calls to probe user read access

> A flaw in the Linux kernel allows user code to bypass read protection checks during LWS compare and swap operations on PA-RISC architecture.

- **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:** 5 Sep 2025
- **Updated:** 12 May 2026
- **Also known as:** AZL-67004, BELL-CVE-2025-39715, DEBIAN-CVE-2025-39715, GHSA-whrv-v478-pw4q, ROOT-OS-DEBIAN-11-CVE-2025-39715, ROOT-OS-DEBIAN-12-CVE-2025-39715, ROOT-OS-DEBIAN-13-CVE-2025-39715, ROOT-OS-UBUNTU-2204-CVE-2025-39715, ROOT-OS-UBUNTU-2404-CVE-2025-39715, UBUNTU-CVE-2025-39715

## What is CVE-2025-39715?

CVE-2025-39715 is a medium-severity vulnerability in Debian Debian Linux, published on 5 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:

parisc: Revise gateway LWS calls to probe user read access

We use load and stbys,e instructions to trigger memory reference
interruptions without writing to memory. Because of the way read
access support is implemented, read access interruptions are only
triggered at privilege levels 2 and 3. The kernel and gateway
page execute at privilege level 0, so this code never triggers
a read access interruption. Thus, it is currently possible for
user code to execute a LWS compare and swap operation at an
address that is read protected at privilege level 3 (PRIV_USER).

Fix this by probing read access rights at privilege level 3 and
branching to lws_fault if access isn't allowed.

## Which versions are affected by CVE-2025-39715?

It affects 2 products.


Products: Debian Debian Linux, Linux kernel.

## How do I fix CVE-2025-39715?

Apply the vendor's patch.

## Is CVE-2025-39715 being exploited?

There is no known exploitation of CVE-2025-39715 in the wild and no public exploit code.

## Other vulnerabilities in Debian Debian Linux

- [CVE-2015-3306](https://insights.sbomify.com/CVE-2015-3306/): ProFTPD Improper Access Control (critical 10.0, exploited in the wild)
- [CVE-2025-49113](https://insights.sbomify.com/CVE-2025-49113/): RoundCube Webmail Deserialization of Untrusted Data (critical 9.9, exploited in the wild)
- [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-2025-39715 and fix it if it is affected.

What it is: CVE-2025-39715 is a medium-severity vulnerability in Debian Debian Linux, published on 5 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-2025-39715 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-2025-39715/ (Markdown: https://insights.sbomify.com/CVE-2025-39715/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2025-39715
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2025-39715
- OSV: https://osv.dev/vulnerability/CVE-2025-39715

---
From sbomify Insights: https://insights.sbomify.com/CVE-2025-39715/
Summaries are generated and may contain mistakes; the official description above is the record.