# CVE-2026-72341: net/mlx5e: Fix publication race for priv->channel_stats[]

> A race condition in the Linux kernel mlx5e driver causes a NULL pointer dereference and system crash when reading network statistics concurrently with channel allocation.

- **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:** 15 Aug 2026
- **Updated:** 21 Oct 2026
- **Also known as:** AZL-96174, BELL-CVE-2026-72341, DEBIAN-CVE-2026-72341, GHSA-rffj-59x2-vrx3, UBUNTU-CVE-2026-72341

## What is CVE-2026-72341?

CVE-2026-72341 is a vulnerability in Linux, published on 15 Aug 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/mlx5e: Fix publication race for priv->channel_stats[]

mlx5e_channel_stats_alloc() publishes a new entry to
priv->channel_stats[] and then increments priv->stats_nch as a
publication token, but neither store carries any memory barrier:

	priv->channel_stats[ix] = kvzalloc_node(...);
	if (!priv->channel_stats[ix])
		return -ENOMEM;
	priv->stats_nch++;

Concurrent readers compute the loop bound from priv->stats_nch and
then dereference priv->channel_stats[i] using plain accesses, e.g.

	for (i = 0; i < priv->stats_nch; i++) {
		struct mlx5e_channel_stats *cs = priv->channel_stats[i];
		... cs->rq.packets ...
	}

On weakly-ordered architectures (ARM, PowerPC, RISC-V) the writes to
channel_stats[ix] and stats_nch may become visible to other CPUs out
of program order. A reader can observe stats_nch == N while still
seeing channel_stats[N-1] == NULL, leading to a NULL pointer
dereference in the channel_stats loop.

This has been observed in production on BlueField-3 DPUs (arm64),
where ovs-vswitchd queries netdev statistics over netlink during NIC
bringup, racing mlx5e_open_channel() -> mlx5e_channel_stats_alloc()
on another CPU:

  Unable to handle kernel NULL pointer dereference at virtual address 0x840
  Hardware name: BlueField-3 DPU
  pc : mlx5e_fold_sw_stats64+0x30/0x180 [mlx5_core]
  Call trace:
   mlx5e_fold_sw_stats64+0x30/0x180 [mlx5_core]
   dev_get_stats+0x50/0xc0
   ovs_vport_get_stats+0x38/0xac [openvswitch]
   ovs_vport_cmd_fill_info+0x194/0x290 [openvswitch]
   ovs_vport_cmd_get+0xbc/0x10c [openvswitch]
   genl_family_rcv_msg_doit+0xd0/0x160
   genl_rcv_msg+0xec/0x1f0
   netlink_rcv_skb+0x64/0x130
   genl_rcv+0x40/0x60
   netlink_unicast+0x2fc/0x370
   netlink_sendmsg+0x1dc/0x454
   ...
   __arm64_sys_sendmsg+0x2c/0x40

Add mlx5e_stats_nch_write() and mlx5e_stats_nch_read() helpers in en.h
that wrap the smp_store_release()/smp_load_acquire() pair on stats_nch.
The release/acquire pair establishes the contract:

  stats_nch == N  =>  channel_stats[0..N-1] are visible and non-NULL.

Publish the stats_nch increment via mlx5e_stats_nch_write() in the
writer (mlx5e_channel_stats_alloc()), and read stats_nch via
mlx5e_stats_nch_read() in all readers: mlx5e RX/TX queue stats,
mlx5e_get_base_stats(), ethtool channels stats, IPoIB stats, the
sw_stats fold and the HV VHCA stats agent.

## Which versions are affected by CVE-2026-72341?


## How do I fix CVE-2026-72341?

Apply the vendor's patch.

## Is CVE-2026-72341 being exploited?

There is no known exploitation of CVE-2026-72341 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-72341 and fix it if it is affected.

What it is: CVE-2026-72341 is a vulnerability in Linux, published on 15 Aug 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-2026-72341 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-2026-72341/ (Markdown: https://insights.sbomify.com/CVE-2026-72341/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-72341
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-72341
- OSV: https://osv.dev/vulnerability/CVE-2026-72341

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-72341/
Summaries are generated and may contain mistakes; the official description above is the record.