# CVE-2026-98257: rds: ib: use rds_conn_drop() on protocol version mismatch

> A deadlock in the Linux kernel RDS InfiniBand driver causes a permanent stall of connection workqueues when a protocol version mismatch occurs.

- **Severity:** High 7.5 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/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:** 6 Oct 2026
- **Updated:** 19 Oct 2026
- **Also known as:** AZL-106431, BELL-CVE-2026-98257, DEBIAN-CVE-2026-98257, GHSA-36mq-8633-f579, UBUNTU-CVE-2026-98257

## What is CVE-2026-98257?

CVE-2026-98257 is a high-severity denial of service vulnerability in Linux, published on 6 Oct 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:

rds: ib: use rds_conn_drop() on protocol version mismatch

rds_ib_cm_connect_complete() runs from the RDMA-CM event handler with
conn->c_cm_lock held.  When the peer negotiates a protocol version
older than RDS_PROTOCOL_COMPAT_VERSION, the handler calls
rds_conn_destroy(), which is only safe in the rmmod path: it
synchronously tears the connection down and flush_work()es the
shutdown work cp_down_w.

That shutdown work (rds_conn_shutdown()) needs cp_cm_lock, which is
the very lock the event handler still holds, so the flush never
completes: the two workers wait on each other and the RDS connection
workqueues stall for good.

All other RDMA-CM failure paths (REJECTED, CONNECT_ERROR,
DISCONNECTED) use rds_conn_drop(), which marks the connection
RDS_CONN_ERROR and schedules the shutdown work asynchronously.  Use
it here as well.

## Which versions are affected by CVE-2026-98257?


## How do I fix CVE-2026-98257?

Apply the vendor's patch.

## Is CVE-2026-98257 being exploited?

There is no known exploitation of CVE-2026-98257 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-98257 and fix it if it is affected.

What it is: CVE-2026-98257 is a high-severity denial of service vulnerability in Linux, published on 6 Oct 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-2026-98257 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-2026-98257/ (Markdown: https://insights.sbomify.com/CVE-2026-98257/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-98257
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-98257
- OSV: https://osv.dev/vulnerability/CVE-2026-98257

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-98257/
Summaries are generated and may contain mistakes; the official description above is the record.