# CVE-2026-98489: net: atl1c: fix soft lockup on out-of-range tpd_cons read

> A remote attacker can cause a kernel soft lockup and system hang by triggering a specific hardware state in the atl1c network driver.

- **Severity:** Not scored
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 18 Oct 2026
- **Updated:** 19 Oct 2026
- **Also known as:** AZL-108698, BELL-CVE-2026-98489, DEBIAN-CVE-2026-98489, GHSA-v9fj-6g8j-jj53, UBUNTU-CVE-2026-98489

## What is CVE-2026-98489?

CVE-2026-98489 is a denial of service vulnerability in Linux, published on 18 Oct 2026. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

In the Linux kernel, the following vulnerability has been resolved:

net: atl1c: fix soft lockup on out-of-range tpd_cons read

The hardware can report an out-of-range tpd_cons (seen as 0xffff)
while the PCIe link/MAC is resetting. An out-of-range value can
never be reached and the loop below would spin forever. To avoid
a soft lockup treat it as "nothing new to clean" instead.

Reproduced on two machines, same NIC (Qualcomm Atheros AR8151 v2.0,
4-port), triggered by rebooting a Mikrotik CCR2004 PCIe card that
the ports are directly linked to:

- Ubuntu 26.04.1 LTS, kernel 7.0.0-31-generic. The link-flap
  precursor, before the lockup was captured with a full trace
  elsewhere:

    atl1c 0000:05:00.0 enp5s0f0: NETDEV WATCHDOG: CPU: 4: transmit queue 2 timed out 489984 ms
    atl1c 0000:05:00.0: MAC state machine can't be idle since disabled for 10ms second
    atl1c 0000:05:00.0: atl1c: enp5s0f0 NIC Link is Up<65535 Mbps Full Duplex>

  65535 (0xffff) here is the same value tpd_cons reads back once the
  loop below gets stuck.

- Proxmox VE, kernel 7.0.14-11-pve. Same NIC/trigger, this time
  caught by the soft lockup watchdog with a full stack trace:

    watchdog: BUG: soft lockup - CPU#12 stuck for 354s! [napi/eth%d-0:329]
    CPU: 12 UID: 0 PID: 329 Comm: napi/eth%d-0 Tainted: P O L 7.0.14-11-pve #1 PREEMPT(lazy)
    RIP: 0010:atl1c_clean_tx+0x142/0x2d0 [atl1c]
    Call Trace:
     <TASK>
     __napi_poll+0x32/0x1e0
     napi_threaded_poll_loop+0x286/0x2e0
     napi_threaded_poll+0xfd/0x140
     kthread+0xf7/0x130
     ret_from_fork+0x2da/0x3a0
     ret_from_fork_asm+0x1a/0x30
     </TASK>

## Which versions are affected by CVE-2026-98489?


## How do I fix CVE-2026-98489?

Apply the vendor's patch.

## Is CVE-2026-98489 being exploited?

There is no known exploitation of CVE-2026-98489 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-98489 and fix it if it is affected.

What it is: CVE-2026-98489 is a denial of service vulnerability in Linux, published on 18 Oct 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-98489 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-2026-98489/ (Markdown: https://insights.sbomify.com/CVE-2026-98489/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-98489
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-98489
- OSV: https://osv.dev/vulnerability/CVE-2026-98489

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-98489/
Summaries are generated and may contain mistakes; the official description above is the record.