# CVE-2021-47160: net: dsa: mt7530: fix VLAN traffic leaks

> An attacker can read traffic from other VLANs when VLAN filtering is disabled due to improper register reset in the mt7530 driver.

- **Severity:** High 8.1 (`CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 25 Mar 2024
- **Updated:** 5 Aug 2026
- **Also known as:** DEBIAN-CVE-2021-47160, GHSA-9r37-jj74-qvw9, UBUNTU-CVE-2021-47160

## What is CVE-2021-47160?

CVE-2021-47160 is a high-severity vulnerability in Linux kernel, published on 25 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: dsa: mt7530: fix VLAN traffic leaks

PCR_MATRIX field was set to all 1's when VLAN filtering is enabled, but
was not reset when it is disabled, which may cause traffic leaks:

	ip link add br0 type bridge vlan_filtering 1
	ip link add br1 type bridge vlan_filtering 1
	ip link set swp0 master br0
	ip link set swp1 master br1
	ip link set br0 type bridge vlan_filtering 0
	ip link set br1 type bridge vlan_filtering 0
	# traffic in br0 and br1 will start leaking to each other

As port_bridge_{add,del} have set up PCR_MATRIX properly, remove the
PCR_MATRIX write from mt7530_port_set_vlan_aware.

## Which versions are affected by CVE-2021-47160?

It affects 1 product.


Products: Linux kernel.

## How do I fix CVE-2021-47160?

Apply the vendor's patch.

## Is CVE-2021-47160 being exploited?

There is no known exploitation of CVE-2021-47160 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-2021-47160 and fix it if it is affected.

What it is: CVE-2021-47160 is a high-severity vulnerability in Linux kernel, published on 25 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-2021-47160 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-2021-47160/ (Markdown: https://insights.sbomify.com/CVE-2021-47160/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2021-47160
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-47160
- OSV: https://osv.dev/vulnerability/CVE-2021-47160

---
From sbomify Insights: https://insights.sbomify.com/CVE-2021-47160/
Summaries are generated and may contain mistakes; the official description above is the record.