# CVE-2026-90098: net: sparx5: fix sleep in atomic context in MAC table access

> A local attacker can trigger a kernel crash by causing the Sparx5 network driver to sleep while holding a lock, resulting in a denial of service.

- **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:** 17 Sep 2026
- **Updated:** 19 Oct 2026
- **Also known as:** AZL-102804, BELL-CVE-2026-90098, DEBIAN-CVE-2026-90098, GHSA-68f7-xq35-m8h9, UBUNTU-CVE-2026-90098

## What is CVE-2026-90098?

CVE-2026-90098 is a denial of service vulnerability in Linux, published on 17 Sep 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: sparx5: fix sleep in atomic context in MAC table access

sparx5_set_rx_mode() runs with netif_addr_lock_bh held and iterates
dev->mc via __dev_mc_sync(), which per address calls sparx5_mc_sync() /
sparx5_mc_unsync() -> sparx5_mact_learn() / sparx5_mact_forget().  These
take sparx5->lock, a mutex, and then poll the MAC access command
register with readx_poll_timeout(). A mutex may block, which is not
allowed from atomic context.

Convert the driver to the new .ndo_set_rx_mode_async callback introduced
in commit 3554b4345d85 ("net: introduce ndo_set_rx_mode_async and
netdev_rx_mode_work"). The async callback is invoked from process
context, so the mutex and sleeping completion poll can remain.

Observed with CONFIG_PROVE_LOCKING, CONFIG_DEBUG_SPINLOCK,
CONFIG_DEBUG_MUTEXES and CONFIG_DEBUG_ATOMIC_SLEEP enabled:

  BUG: sleeping function called from invalid context at kernel/locking/mutex.c:591
  in_atomic(): 1, irqs_disabled(): 0, non_block: 0, pid: 217, name: ip
  preempt_count: 201, expected: 0
  Call trace:
   __might_resched+0x144/0x248
   __might_sleep+0x48/0x7c
   __mutex_lock+0x74/0x850
   mutex_lock_nested+0x24/0x30
   sparx5_mact_learn+0x78/0x100
   sparx5_mc_sync+0x40/0x54
   __hw_addr_sync_dev+0xc4/0x170
   sparx5_set_rx_mode+0x4c/0x58
   __dev_set_rx_mode+0x64/0xa4
   __dev_open+0x1ec/0x26c

## Which versions are affected by CVE-2026-90098?


## How do I fix CVE-2026-90098?

Apply the vendor's patch.

## Is CVE-2026-90098 being exploited?

There is no known exploitation of CVE-2026-90098 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-90098 and fix it if it is affected.

What it is: CVE-2026-90098 is a denial of service vulnerability in Linux, published on 17 Sep 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-2026-90098 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-2026-90098/ (Markdown: https://insights.sbomify.com/CVE-2026-90098/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-90098
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-90098
- OSV: https://osv.dev/vulnerability/CVE-2026-90098

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-90098/
Summaries are generated and may contain mistakes; the official description above is the record.