# CVE-2023-52574: team: fix null-ptr-deref when team device type is changed

> A null pointer dereference in the Linux kernel team driver allows local attackers to cause a system crash by changing device types.

- **Severity:** High 7.8 (`CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/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:** 2 Mar 2024
- **Updated:** 5 Aug 2026
- **Also known as:** BELL-CVE-2023-52574, DEBIAN-CVE-2023-52574, GHSA-6vm2-4jg8-fq6m, UBUNTU-CVE-2023-52574

## What is CVE-2023-52574?

CVE-2023-52574 is a high-severity vulnerability in Linux kernel, published on 2 Mar 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:

team: fix null-ptr-deref when team device type is changed

Get a null-ptr-deref bug as follows with reproducer [1].

BUG: kernel NULL pointer dereference, address: 0000000000000228
...
RIP: 0010:vlan_dev_hard_header+0x35/0x140 [8021q]
...
Call Trace:
 <TASK>
 ? __die+0x24/0x70
 ? page_fault_oops+0x82/0x150
 ? exc_page_fault+0x69/0x150
 ? asm_exc_page_fault+0x26/0x30
 ? vlan_dev_hard_header+0x35/0x140 [8021q]
 ? vlan_dev_hard_header+0x8e/0x140 [8021q]
 neigh_connected_output+0xb2/0x100
 ip6_finish_output2+0x1cb/0x520
 ? nf_hook_slow+0x43/0xc0
 ? ip6_mtu+0x46/0x80
 ip6_finish_output+0x2a/0xb0
 mld_sendpack+0x18f/0x250
 mld_ifc_work+0x39/0x160
 process_one_work+0x1e6/0x3f0
 worker_thread+0x4d/0x2f0
 ? __pfx_worker_thread+0x10/0x10
 kthread+0xe5/0x120
 ? __pfx_kthread+0x10/0x10
 ret_from_fork+0x34/0x50
 ? __pfx_kthread+0x10/0x10
 ret_from_fork_asm+0x1b/0x30

[1]
$ teamd -t team0 -d -c '{"runner": {"name": "loadbalance"}}'
$ ip link add name t-dummy type dummy
$ ip link add link t-dummy name t-dummy.100 type vlan id 100
$ ip link add name t-nlmon type nlmon
$ ip link set t-nlmon master team0
$ ip link set t-nlmon nomaster
$ ip link set t-dummy up
$ ip link set team0 up
$ ip link set t-dummy.100 down
$ ip link set t-dummy.100 master team0

When enslave a vlan device to team device and team device type is changed
from non-ether to ether, header_ops of team device is changed to
vlan_header_ops. That is incorrect and will trigger null-ptr-deref
for vlan->real_dev in vlan_dev_hard_header() because team device is not
a vlan device.

Cache eth_header_ops in team_setup(), then assign cached header_ops to
header_ops of team net device when its type is changed from non-ether
to ether to fix the bug.

Weakness: CWE-476 (NULL Pointer Dereference)

## Which versions are affected by CVE-2023-52574?

It affects 1 product.


Products: Linux kernel.

## How do I fix CVE-2023-52574?

Apply the vendor's patch.

## Is CVE-2023-52574 being exploited?

There is no known exploitation of CVE-2023-52574 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-2023-52574 and fix it if it is affected.

What it is: CVE-2023-52574 is a high-severity vulnerability in Linux kernel, published on 2 Mar 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-2023-52574 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-2023-52574/ (Markdown: https://insights.sbomify.com/CVE-2023-52574/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2023-52574
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2023-52574
- OSV: https://osv.dev/vulnerability/CVE-2023-52574

---
From sbomify Insights: https://insights.sbomify.com/CVE-2023-52574/
Summaries are generated and may contain mistakes; the official description above is the record.