# CVE-2024-26698: hv_netvsc: Fix race condition between netvsc_probe and netvsc_remove

> A race condition in the Linux kernel's Hyper-V network driver can cause a system hang during device removal, leading to denial of service.

- **Severity:** Medium 4.7 (`CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 3 Apr 2024
- **Updated:** 11 May 2026
- **Also known as:** BELL-CVE-2024-26698, DEBIAN-CVE-2024-26698, GHSA-7g56-3wmh-7x3p, UBUNTU-CVE-2024-26698

## What is CVE-2024-26698?

CVE-2024-26698 is a medium-severity vulnerability in Debian Debian Linux, published on 3 Apr 2024. 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:

hv_netvsc: Fix race condition between netvsc_probe and netvsc_remove

In commit ac5047671758 ("hv_netvsc: Disable NAPI before closing the
VMBus channel"), napi_disable was getting called for all channels,
including all subchannels without confirming if they are enabled or not.

This caused hv_netvsc getting hung at napi_disable, when netvsc_probe()
has finished running but nvdev->subchan_work has not started yet.
netvsc_subchan_work() -> rndis_set_subchannel() has not created the
sub-channels and because of that netvsc_sc_open() is not running.
netvsc_remove() calls cancel_work_sync(&nvdev->subchan_work), for which
netvsc_subchan_work did not run.

netif_napi_add() sets the bit NAPI_STATE_SCHED because it ensures NAPI
cannot be scheduled. Then netvsc_sc_open() -> napi_enable will clear the
NAPIF_STATE_SCHED bit, so it can be scheduled. napi_disable() does the
opposite.

Now during netvsc_device_remove(), when napi_disable is called for those
subchannels, napi_disable gets stuck on infinite msleep.

This fix addresses this problem by ensuring that napi_disable() is not
getting called for non-enabled NAPI struct.
But netif_napi_del() is still necessary for these non-enabled NAPI struct
for cleanup purpose.

Call trace:
[  654.559417] task:modprobe        state:D stack:    0 pid: 2321 ppid:  1091 flags:0x00004002
[  654.568030] Call Trace:
[  654.571221]  <TASK>
[  654.573790]  __schedule+0x2d6/0x960
[  654.577733]  schedule+0x69/0xf0
[  654.581214]  schedule_timeout+0x87/0x140
[  654.585463]  ? __bpf_trace_tick_stop+0x20/0x20
[  654.590291]  msleep+0x2d/0x40
[  654.593625]  napi_disable+0x2b/0x80
[  654.597437]  netvsc_device_remove+0x8a/0x1f0 [hv_netvsc]
[  654.603935]  rndis_filter_device_remove+0x194/0x1c0 [hv_netvsc]
[  654.611101]  ? do_wait_intr+0xb0/0xb0
[  654.615753]  netvsc_remove+0x7c/0x120 [hv_netvsc]
[  654.621675]  vmbus_remove+0x27/0x40 [hv_vmbus]

Weakness: CWE-362 (Concurrent Execution using Shared Resource with Improper Synchronization)

## Which versions are affected by CVE-2024-26698?

It affects 2 products.


Products: Debian Debian Linux, Linux kernel.

## How do I fix CVE-2024-26698?

Apply the vendor's patch.

## Is CVE-2024-26698 being exploited?

There is no known exploitation of CVE-2024-26698 in the wild and no public exploit code.

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- [CVE-2024-9680](https://insights.sbomify.com/CVE-2024-9680/): Mozilla Firefox Use-After-Free (critical 9.8, exploited in the wild)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2024-26698 and fix it if it is affected.

What it is: CVE-2024-26698 is a medium-severity vulnerability in Debian Debian Linux, published on 3 Apr 2024. 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-2024-26698 in the wild and no public exploit code.

Affected product: Debian Debian 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-2024-26698/ (Markdown: https://insights.sbomify.com/CVE-2024-26698/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2024-26698
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2024-26698
- OSV: https://osv.dev/vulnerability/CVE-2024-26698

---
From sbomify Insights: https://insights.sbomify.com/CVE-2024-26698/
Summaries are generated and may contain mistakes; the official description above is the record.
