# CVE-2025-38048: virtio_ring: Fix data race by tagging event_triggered as racy for KCSAN

> A data race in the Linux kernel's virtio_ring driver can cause temporary notification delays, potentially 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:** 18 Jun 2025
- **Updated:** 11 May 2026
- **Also known as:** BELL-CVE-2025-38048, DEBIAN-CVE-2025-38048, GHSA-3mg3-84hp-h85m, ROOT-OS-DEBIAN-11-CVE-2025-38048, ROOT-OS-DEBIAN-12-CVE-2025-38048, ROOT-OS-UBUNTU-2204-CVE-2025-38048, ROOT-OS-UBUNTU-2404-CVE-2025-38048, UBUNTU-CVE-2025-38048

## What is CVE-2025-38048?

CVE-2025-38048 is a medium-severity vulnerability in Debian Debian Linux, published on 18 Jun 2025. 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:

virtio_ring: Fix data race by tagging event_triggered as racy for KCSAN

syzbot reports a data-race when accessing the event_triggered, here is the
simplified stack when the issue occurred:

==================================================================
BUG: KCSAN: data-race in virtqueue_disable_cb / virtqueue_enable_cb_delayed

write to 0xffff8881025bc452 of 1 bytes by task 3288 on cpu 0:
 virtqueue_enable_cb_delayed+0x42/0x3c0 drivers/virtio/virtio_ring.c:2653
 start_xmit+0x230/0x1310 drivers/net/virtio_net.c:3264
 __netdev_start_xmit include/linux/netdevice.h:5151 [inline]
 netdev_start_xmit include/linux/netdevice.h:5160 [inline]
 xmit_one net/core/dev.c:3800 [inline]

read to 0xffff8881025bc452 of 1 bytes by interrupt on cpu 1:
 virtqueue_disable_cb_split drivers/virtio/virtio_ring.c:880 [inline]
 virtqueue_disable_cb+0x92/0x180 drivers/virtio/virtio_ring.c:2566
 skb_xmit_done+0x5f/0x140 drivers/net/virtio_net.c:777
 vring_interrupt+0x161/0x190 drivers/virtio/virtio_ring.c:2715
 __handle_irq_event_percpu+0x95/0x490 kernel/irq/handle.c:158
 handle_irq_event_percpu kernel/irq/handle.c:193 [inline]

value changed: 0x01 -> 0x00
==================================================================

When the data race occurs, the function virtqueue_enable_cb_delayed() sets
event_triggered to false, and virtqueue_disable_cb_split/packed() reads it
as false due to the race condition. Since event_triggered is an unreliable
hint used for optimization, this should only cause the driver temporarily
suggest that the device not send an interrupt notification when the event
index is used.

Fix this KCSAN reported data-race issue by explicitly tagging the access as
data_racy.

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

## Which versions are affected by CVE-2025-38048?

It affects 2 products.


Products: Debian Debian Linux, Linux kernel.

## How do I fix CVE-2025-38048?

Apply the vendor's patch.

## Is CVE-2025-38048 being exploited?

There is no known exploitation of CVE-2025-38048 in the wild and no public exploit code.

## Other vulnerabilities in Debian Debian Linux

- [CVE-2015-3306](https://insights.sbomify.com/CVE-2015-3306/): ProFTPD Improper Access Control (critical 10.0, exploited in the wild)
- [CVE-2025-49113](https://insights.sbomify.com/CVE-2025-49113/): RoundCube Webmail Deserialization of Untrusted Data (critical 9.9, exploited in the wild)
- [CVE-2026-24061](https://insights.sbomify.com/CVE-2026-24061/): GNU InetUtils Argument Injection (critical 9.8, exploited in the wild)
- [CVE-2025-39682](https://insights.sbomify.com/CVE-2025-39682/): Linux Kernel Improper Check for Unusual or Exceptional Conditions (critical 9.8, exploited in the wild)
- [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-2025-38048 and fix it if it is affected.

What it is: CVE-2025-38048 is a medium-severity vulnerability in Debian Debian Linux, published on 18 Jun 2025. 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-2025-38048 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-2025-38048/ (Markdown: https://insights.sbomify.com/CVE-2025-38048/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2025-38048
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2025-38048
- OSV: https://osv.dev/vulnerability/CVE-2025-38048

---
From sbomify Insights: https://insights.sbomify.com/CVE-2025-38048/
Summaries are generated and may contain mistakes; the official description above is the record.