# CVE-2021-47102: net: marvell: prestera: fix incorrect structure access

> A memory access error in the Marvell Prestera network driver can cause a kernel crash when handling specific network device events.

- **Severity:** High 7.1 (`CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/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:** 4 Mar 2024
- **Updated:** 5 Aug 2026
- **Also known as:** DEBIAN-CVE-2021-47102, GHSA-vh9v-w8ph-h8v5, UBUNTU-CVE-2021-47102

## What is CVE-2021-47102?

CVE-2021-47102 is a high-severity memory corruption vulnerability in Linux kernel, published on 4 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:

net: marvell: prestera: fix incorrect structure access

In line:
	upper = info->upper_dev;
We access upper_dev field, which is related only for particular events
(e.g. event == NETDEV_CHANGEUPPER). So, this line cause invalid memory
access for another events,
when ptr is not netdev_notifier_changeupper_info.

The KASAN logs are as follows:

[   30.123165] BUG: KASAN: stack-out-of-bounds in prestera_netdev_port_event.constprop.0+0x68/0x538 [prestera]
[   30.133336] Read of size 8 at addr ffff80000cf772b0 by task udevd/778
[   30.139866]
[   30.141398] CPU: 0 PID: 778 Comm: udevd Not tainted 5.16.0-rc3 #6
[   30.147588] Hardware name: DNI AmazonGo1 A7040 board (DT)
[   30.153056] Call trace:
[   30.155547]  dump_backtrace+0x0/0x2c0
[   30.159320]  show_stack+0x18/0x30
[   30.162729]  dump_stack_lvl+0x68/0x84
[   30.166491]  print_address_description.constprop.0+0x74/0x2b8
[   30.172346]  kasan_report+0x1e8/0x250
[   30.176102]  __asan_load8+0x98/0xe0
[   30.179682]  prestera_netdev_port_event.constprop.0+0x68/0x538 [prestera]
[   30.186847]  prestera_netdev_event_handler+0x1b4/0x1c0 [prestera]
[   30.193313]  raw_notifier_call_chain+0x74/0xa0
[   30.197860]  call_netdevice_notifiers_info+0x68/0xc0
[   30.202924]  register_netdevice+0x3cc/0x760
[   30.207190]  register_netdev+0x24/0x50
[   30.211015]  prestera_device_register+0x8a0/0xba0 [prestera]

Weakness: CWE-125 (Out-of-bounds Read)

## Which versions are affected by CVE-2021-47102?

It affects 1 product.


Products: Linux kernel.

## How do I fix CVE-2021-47102?

Apply the vendor's patch.

## Is CVE-2021-47102 being exploited?

There is no known exploitation of CVE-2021-47102 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-2021-47102 and fix it if it is affected.

What it is: CVE-2021-47102 is a high-severity memory corruption vulnerability in Linux kernel, published on 4 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-2021-47102 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-2021-47102/ (Markdown: https://insights.sbomify.com/CVE-2021-47102/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2021-47102
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-47102
- OSV: https://osv.dev/vulnerability/CVE-2021-47102

---
From sbomify Insights: https://insights.sbomify.com/CVE-2021-47102/
Summaries are generated and may contain mistakes; the official description above is the record.