# CVE-2026-89535: svcrdma: Reorder rpcrdma_rn_unregister before rdma_destroy_id

> A use-after-free vulnerability in the Linux kernel's svcrdma module allows attackers to cause denial of service or potentially execute code via race conditions during device unregistration.

- **Severity:** High 8.1 (`CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 11 Sep 2026
- **Updated:** 19 Oct 2026
- **Also known as:** BELL-CVE-2026-89535, DEBIAN-CVE-2026-89535, GHSA-xqw2-jp99-qfhh, UBUNTU-CVE-2026-89535

## What is CVE-2026-89535?

CVE-2026-89535 is a high-severity use after free vulnerability in Linux, published on 11 Sep 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

In the Linux kernel, the following vulnerability has been resolved:

svcrdma: Reorder rpcrdma_rn_unregister before rdma_destroy_id

svc_rdma_free() caches rdma->sc_cm_id->device before teardown,
then calls rdma_destroy_id(sc_cm_id) which frees the cm_id.
rpcrdma_rn_unregister() follows, but between those two calls
the transport's sc_rn entry is still installed in the device's
rd_xa. A concurrent ib_unregister_device walk can dispatch
svc_rdma_xprt_done() against the now-freed sc_cm_id.

Move rpcrdma_rn_unregister() before rdma_destroy_id() so the
transport's notification entry is removed from the xarray before
the cm_id it references is destroyed.

Also guard the sc_cm_id dereference with a NULL check: the
following patches introduce paths that reach svc_rdma_free()
with sc_cm_id == NULL (listener create failure, ADDR_CHANGE
replacement failure).

## Which versions are affected by CVE-2026-89535?


## How do I fix CVE-2026-89535?

Apply the vendor's patch.

## Is CVE-2026-89535 being exploited?

There is no known exploitation of CVE-2026-89535 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-89535 and fix it if it is affected.

What it is: CVE-2026-89535 is a high-severity use after free vulnerability in Linux, published on 11 Sep 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-89535 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-2026-89535/ (Markdown: https://insights.sbomify.com/CVE-2026-89535/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-89535
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-89535
- OSV: https://osv.dev/vulnerability/CVE-2026-89535

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-89535/
Summaries are generated and may contain mistakes; the official description above is the record.