# CVE-2022-48647: sfc: fix TX channel offset when using legacy interrupts

> A null pointer dereference in the sfc network driver causes a kernel crash when sending traffic in legacy interrupt mode with specific channel configurations.

- **Severity:** Medium 5.5 (`CVSS:3.1/AV:L/AC:L/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:** 28 Apr 2024
- **Updated:** 23 May 2026
- **Also known as:** DEBIAN-CVE-2022-48647, GHSA-xxhf-v2m2-422x, UBUNTU-CVE-2022-48647

## What is CVE-2022-48647?

CVE-2022-48647 is a medium-severity vulnerability in Linux kernel, published on 28 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:

sfc: fix TX channel offset when using legacy interrupts

In legacy interrupt mode the tx_channel_offset was hardcoded to 1, but
that's not correct if efx_sepparate_tx_channels is false. In that case,
the offset is 0 because the tx queues are in the single existing channel
at index 0, together with the rx queue.

Without this fix, as soon as you try to send any traffic, it tries to
get the tx queues from an uninitialized channel getting these errors:
  WARNING: CPU: 1 PID: 0 at drivers/net/ethernet/sfc/tx.c:540 efx_hard_start_xmit+0x12e/0x170 [sfc]
  [...]
  RIP: 0010:efx_hard_start_xmit+0x12e/0x170 [sfc]
  [...]
  Call Trace:
   <IRQ>
   dev_hard_start_xmit+0xd7/0x230
   sch_direct_xmit+0x9f/0x360
   __dev_queue_xmit+0x890/0xa40
  [...]
  BUG: unable to handle kernel NULL pointer dereference at 0000000000000020
  [...]
  RIP: 0010:efx_hard_start_xmit+0x153/0x170 [sfc]
  [...]
  Call Trace:
   <IRQ>
   dev_hard_start_xmit+0xd7/0x230
   sch_direct_xmit+0x9f/0x360
   __dev_queue_xmit+0x890/0xa40
  [...]

Weakness: CWE-476 (NULL Pointer Dereference)

## Which versions are affected by CVE-2022-48647?

It affects 1 product.


Products: Linux kernel.

## How do I fix CVE-2022-48647?

Apply the vendor's patch.

## Is CVE-2022-48647 being exploited?

There is no known exploitation of CVE-2022-48647 in the wild and no public exploit code.

## Other vulnerabilities in Linux kernel

- [CVE-2026-53266](https://insights.sbomify.com/CVE-2026-53266/): Linux Kernel Out-of-Bounds Write (high 8.8, exploited in the wild)
- [CVE-2013-6282](https://insights.sbomify.com/CVE-2013-6282/): Linux Kernel Improper Input Validation (high 8.8, exploited in the wild)
- [CVE-2022-0185](https://insights.sbomify.com/CVE-2022-0185/): Linux Kernel Heap-Based Buffer Overflow (high 8.4, exploited in the wild)
- [CVE-2013-2094](https://insights.sbomify.com/CVE-2013-2094/): Linux Kernel Privilege Escalation (high 8.4, exploited in the wild)
- [CVE-2026-53362](https://insights.sbomify.com/CVE-2026-53362/): Linux Kernel Unspecified (high 7.8, exploited in the wild)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2022-48647 and fix it if it is affected.

What it is: CVE-2022-48647 is a medium-severity vulnerability in Linux kernel, published on 28 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-2022-48647 in the wild and no public exploit code.

Affected product: Linux kernel. 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-2022-48647/ (Markdown: https://insights.sbomify.com/CVE-2022-48647/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2022-48647
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2022-48647
- OSV: https://osv.dev/vulnerability/CVE-2022-48647

---
From sbomify Insights: https://insights.sbomify.com/CVE-2022-48647/
Summaries are generated and may contain mistakes; the official description above is the record.