# CVE-2026-80980: net/smc: stop killed, freed and out_of_sync sharing a byte

> A race condition in Linux kernel SMC networking allows concurrent flag updates to corrupt connection state, potentially causing data corruption or crashes.

- **Severity:** Critical 9.8 (`CVSS:3.1/AV:N/AC:L/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:** 21 Oct 2026
- **Also known as:** AZL-100361, BELL-CVE-2026-80980, DEBIAN-CVE-2026-80980, GHSA-74wv-6pxv-7x55, UBUNTU-CVE-2026-80980

## What is CVE-2026-80980?

CVE-2026-80980 is a critical 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: stop killed, freed and out_of_sync sharing a byte

The three connection state flags are single-bit bitfields, so they occupy
one byte of struct smc_connection and every store to one is a
read-modify-write of the other two:

    u8  killed : 1;
    u8  freed : 1;
    u8  out_of_sync : 1;

They are not written under a common lock. smc_cdc_msg_validate() sets
out_of_sync from the receive tasklet, while smc_conn_kill() sets killed
from process context under lock_sock(), and the receive path does not defer
to the backlog when the socket is owned -- smc_cdc_msg_recv() takes only
bh_lock_sock().

Give each flag its own byte so a store no longer touches its neighbours.
All readers test them as booleans and are unchanged. struct smc_connection
grows by two bytes.

## Which versions are affected by CVE-2026-80980?


## How do I fix CVE-2026-80980?

Apply the vendor's patch.

## Is CVE-2026-80980 being exploited?

There is no known exploitation of CVE-2026-80980 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-80980 and fix it if it is affected.

What it is: CVE-2026-80980 is a critical 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-2026-80980 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-2026-80980/ (Markdown: https://insights.sbomify.com/CVE-2026-80980/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-80980
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-80980
- OSV: https://osv.dev/vulnerability/CVE-2026-80980

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-80980/
Summaries are generated and may contain mistakes; the official description above is the record.