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

Severity: high (CVSS 7.1 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.3% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2024-03-25 · updated 2026-08-04

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.

Affected products

Linux kernel: from 4.16 before 4.19.193; from 4.20 before 5.4.124; from 5.5 before 5.10.42; from 5.11 before 5.12.9; 5.13-rc1, 5.13-rc2, 5.13-rc3 — fixed in 4.19.193, 5.10.42, 5.12.9, 5.4.124

How to fix

Upgrade to a fixed version: Linux kernel 4.19.193, 5.10.42, 5.12.9, 5.4.124. Check the vendor advisory for mitigations.

References

Get alerted when CVE-2021-47160 or the next vulnerability affects your stack