# CVE-2026-98562: net: libwx: fix races in Tx timestamp handling

> A race condition in the Linux kernel libwx driver allows attackers to trigger use-after-free or memory leaks, potentially causing denial of service or code execution.

- **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:** 18 Oct 2026
- **Updated:** 19 Oct 2026
- **Also known as:** BELL-CVE-2026-98562, DEBIAN-CVE-2026-98562, GHSA-44w9-74gm-gcrx, UBUNTU-CVE-2026-98562

## What is CVE-2026-98562?

CVE-2026-98562 is a vulnerability in Linux, published on 18 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:

net: libwx: fix races in Tx timestamp handling

wx->ptp_tx_skb is shared between the Tx path, the PTP auxiliary
worker and the timestamp cleanup paths. The
WX_STATE_PTP_TX_IN_PROGRESS bit prevents multiple Tx paths from
submitting timestamp requests, but does not serialize the worker
against cleanup.

As a result, wx_ptp_clear_tx_timestamp() can free an skb after
wx_ptp_tx_hwtstamp_work() has obtained its pointer. The worker may
then pass the freed skb to skb_tstamp_tx() and release the same
reference again.

The cleanup path may also clear the in-progress bit while the worker
is still processing the old skb. This allows the Tx path to publish a
new skb which the worker can subsequently overwrite with NULL,
leaking its reference.

Add a dedicated spinlock to protect publication and consumption of
the Tx timestamp skb. Detach the skb and clear the in-progress bit
while holding the lock, then deliver the timestamp and release the skb
after dropping it. Use the same locked cleanup in the quiesce path,
but keep the detach there free of register accesses: quiesce runs
during PCIe error recovery, where MMIO is not reliable, and it
deliberately did not touch the device before. The lock is taken with
interrupts disabled, because netpoll can call ndo_start_xmit() with
hard interrupts already off.

When handling a Tx DMA mapping failure, keep the transmit path
reference until after comparing the skb under the lock. This prevents
skb address reuse from making the error path mistake a newer timestamp
request for the failed one.

## Which versions are affected by CVE-2026-98562?


## How do I fix CVE-2026-98562?

Apply the vendor's patch.

## Is CVE-2026-98562 being exploited?

There is no known exploitation of CVE-2026-98562 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-98562 and fix it if it is affected.

What it is: CVE-2026-98562 is a vulnerability in Linux, published on 18 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-2026-98562 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-2026-98562/ (Markdown: https://insights.sbomify.com/CVE-2026-98562/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-98562
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-98562
- OSV: https://osv.dev/vulnerability/CVE-2026-98562

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-98562/
Summaries are generated and may contain mistakes; the official description above is the record.