# CVE-2026-89489: openrisc: fix arbitrary kernel memory access via or1k_atomic syscall

> An unprivileged user can exploit missing pointer checks in the OpenRISC atomic syscall to read/write kernel memory and execute code with kernel privileges.

- **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 2026
- **Updated:** 19 Oct 2026
- **Also known as:** AZL-100697, BELL-CVE-2026-89489, DEBIAN-CVE-2026-89489, GHSA-9rpr-c8j9-pwgc, UBUNTU-CVE-2026-89489

## What is CVE-2026-89489?

CVE-2026-89489 is a high-severity memory corruption vulnerability in Linux, published on 11 Sep 2026. 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:

openrisc: fix arbitrary kernel memory access via or1k_atomic syscall

sys_or1k_atomic() (syscall 244 in the "or1k" ABI) takes two user
pointers, v1 and v2, and swaps the words they point to in hand-written
assembly.

    l.lwz   r29,0(r4)
    l.lwz   r27,0(r5)
    l.sw    0(r4),r27
    l.sw    0(r5),r29

The pointers are not checked with access_ok(). The four memory
accesses also have no exception table entries.

A caller passes a kernel address as either pointer, and the syscall
reads from and writes to it directly.

This gives an unprivileged process a kernel read/write primitive. It
overwrites kernel data such as the sys_call_table, gaining code
execution in kernel context.

Check both pointers before entering the critical section. Add fixups
for the four memory accesses so faults on valid but unmapped user
addresses return -EFAULT.

[shorne@gmail.com: fix comment style]

## Which versions are affected by CVE-2026-89489?


## How do I fix CVE-2026-89489?

Apply the vendor's patch.

## Is CVE-2026-89489 being exploited?

There is no known exploitation of CVE-2026-89489 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-89489 and fix it if it is affected.

What it is: CVE-2026-89489 is a high-severity memory corruption vulnerability in Linux, published on 11 Sep 2026. 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-2026-89489 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-2026-89489/ (Markdown: https://insights.sbomify.com/CVE-2026-89489/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-89489
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-89489
- OSV: https://osv.dev/vulnerability/CVE-2026-89489

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-89489/
Summaries are generated and may contain mistakes; the official description above is the record.