# CVE-2026-98072: net/rds: use wq_has_sleeper() in release_in_xmit()

> A race condition in the Linux kernel RDS module can cause a lost wake-up, leading to a denial of service by hanging connection shutdown workers.

- **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:** 25 Sep 2026
- **Updated:** 19 Oct 2026
- **Also known as:** AZL-104214, BELL-CVE-2026-98072, DEBIAN-CVE-2026-98072, GHSA-6xgx-8jc3-whpq, UBUNTU-CVE-2026-98072

## What is CVE-2026-98072?

CVE-2026-98072 is a vulnerability in Linux, published on 25 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/rds: use wq_has_sleeper() in release_in_xmit()

release_in_xmit() clears RDS_IN_XMIT with clear_bit_unlock() and then
checks waitqueue_active() to decide whether anyone needs waking.
clear_bit_unlock() is only a release operation: it orders the
critical section before the bit clear, but does not order the
subsequent plain load of the wait queue head after it.  The waiter
side does the mirror image - it adds itself to the wait queue and
then tests the bit.  That is the classic store-buffering pattern: the
releasing CPU can read the wait queue as empty while the waiting CPU
still reads the bit as set, so the sleeper is never woken.

The waiters are rds_conn_shutdown() and rds_tcp_reset_callbacks(),
both in uninterruptible wait_event() with no timeout.  A lost wake-up
strands the shutdown worker on its single-threaded workqueue until
some other sender releases the bit again - and on a connection that
is being torn down precisely because it failed, there may never be
another sender.

The barrier used to be there: release_in_xmit() did clear_bit()
followed by smp_mb__after_atomic() until commit 1422f28826d2 ("rds:
introduce acquire/release ordering in acquire/release_in_xmit()")
folded both into clear_bit_unlock(), which strengthened the lock
hand-off but silently dropped the full barrier the wake-up check
depends on.  The refill counterpart, release_refill() in
net/rds/ib_recv.c, still carries its smp_mb__after_atomic() for
exactly this reason.

Use wq_has_sleeper(), which is waitqueue_active() preceded by the
required full barrier.

## Which versions are affected by CVE-2026-98072?


## How do I fix CVE-2026-98072?

Apply the vendor's patch.

## Is CVE-2026-98072 being exploited?

There is no known exploitation of CVE-2026-98072 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-98072 and fix it if it is affected.

What it is: CVE-2026-98072 is a vulnerability in Linux, published on 25 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-2026-98072 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-2026-98072/ (Markdown: https://insights.sbomify.com/CVE-2026-98072/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-98072
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-98072
- OSV: https://osv.dev/vulnerability/CVE-2026-98072

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-98072/
Summaries are generated and may contain mistakes; the official description above is the record.