# CVE-2022-49021: net: phy: fix null-ptr-deref while probe() failed

> A null pointer dereference in the Linux kernel network PHY driver can cause a system crash when device probing fails.

- **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:** 21 Oct 2024
- **Updated:** 11 May 2026
- **Also known as:** DEBIAN-CVE-2022-49021, GHSA-44h7-hpp5-qghj, UBUNTU-CVE-2022-49021

## What is CVE-2022-49021?

CVE-2022-49021 is a medium-severity vulnerability in Linux kernel, published on 21 Oct 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:

net: phy: fix null-ptr-deref while probe() failed

I got a null-ptr-deref report as following when doing fault injection test:

BUG: kernel NULL pointer dereference, address: 0000000000000058
Oops: 0000 [#1] PREEMPT SMP KASAN PTI
CPU: 1 PID: 253 Comm: 507-spi-dm9051 Tainted: G    B            N 6.1.0-rc3+
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.13.0-1ubuntu1.1 04/01/2014
RIP: 0010:klist_put+0x2d/0xd0
Call Trace:
 <TASK>
 klist_remove+0xf1/0x1c0
 device_release_driver_internal+0x23e/0x2d0
 bus_remove_device+0x1bd/0x240
 device_del+0x357/0x770
 phy_device_remove+0x11/0x30
 mdiobus_unregister+0xa5/0x140
 release_nodes+0x6a/0xa0
 devres_release_all+0xf8/0x150
 device_unbind_cleanup+0x19/0xd0

//probe path:
phy_device_register()
  device_add()

phy_connect
  phy_attach_direct() //set device driver
    probe() //it's failed, driver is not bound
    device_bind_driver() // probe failed, it's not called

//remove path:
phy_device_remove()
  device_del()
    device_release_driver_internal()
      __device_release_driver() //dev->drv is not NULL
        klist_remove() <- knode_driver is not added yet, cause null-ptr-deref

In phy_attach_direct(), after setting the 'dev->driver', probe() fails,
device_bind_driver() is not called, so the knode_driver->n_klist is not
set, then it causes null-ptr-deref in __device_release_driver() while
deleting device. Fix this by setting dev->driver to NULL in the error
path in phy_attach_direct().

Weakness: CWE-476 (NULL Pointer Dereference)

## Which versions are affected by CVE-2022-49021?

It affects 1 product.


Products: Linux kernel.

## How do I fix CVE-2022-49021?

Apply the vendor's patch.

## Is CVE-2022-49021 being exploited?

There is no known exploitation of CVE-2022-49021 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-2022-49021 and fix it if it is affected.

What it is: CVE-2022-49021 is a medium-severity vulnerability in Linux kernel, published on 21 Oct 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-2022-49021 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-2022-49021/ (Markdown: https://insights.sbomify.com/CVE-2022-49021/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2022-49021
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2022-49021
- OSV: https://osv.dev/vulnerability/CVE-2022-49021

---
From sbomify Insights: https://insights.sbomify.com/CVE-2022-49021/
Summaries are generated and may contain mistakes; the official description above is the record.