# CVE-2026-80984: net/smc: do not dereference an unset send buffer on the SMC-D teardown path

> A null pointer dereference in the Linux kernel SMC-D teardown path allows remote attackers to cause a denial of service via crafted network traffic.

- **Severity:** Not scored
- **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:** AZL-100223, BELL-CVE-2026-80984, DEBIAN-CVE-2026-80984, GHSA-r783-4vmj-f363, UBUNTU-CVE-2026-80984

## What is CVE-2026-80984?

CVE-2026-80984 is a 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:

net/smc: do not dereference an unset send buffer on the SMC-D teardown path

smc_close_stream_wait() calls smc_tx_prepared_sends() from inside its
sk_wait_event() condition, and sk_wait_event() evaluates that condition
once with the socket lock released. smcd_buf_detach() clears
conn->sndbuf_desc from smc_conn_kill() under lock_sock(), so a link group
terminating while a socket waits there leaves the helper dereferencing
NULL, faulting out of close(). SIOCOUTQ reads the field by hand, and
smc_close_cancel_work() drops the lock across two cancel_*_sync() calls.

Sample the pointer once in the helper, report nothing prepared while it is
unset, and bound the ioctl the same way. The receive tasklet dereferences
the field directly in smc_cdc_msg_recv_action(), not through this helper;
1/2 is what keeps it from running that late.

## Which versions are affected by CVE-2026-80984?


## How do I fix CVE-2026-80984?

Apply the vendor's patch.

## Is CVE-2026-80984 being exploited?

There is no known exploitation of CVE-2026-80984 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-80984 and fix it if it is affected.

What it is: CVE-2026-80984 is a 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-2026-80984 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-2026-80984/ (Markdown: https://insights.sbomify.com/CVE-2026-80984/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-80984
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-80984
- OSV: https://osv.dev/vulnerability/CVE-2026-80984

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-80984/
Summaries are generated and may contain mistakes; the official description above is the record.