CVE-2026-68301

/// Technical description

In the Linux kernel, the following vulnerability has been resolved:

net: hsr: fix memory leak on slave unregistration by removing synced VLANs

When an HSR master device is brought UP, it auto-adds VLAN 0 via

vlan_vid0_add(), which propagates VID 0 to its slave devices (slave A and B).

If a slave device is later unregistered while HSR is active (e.g., during

netns cleanup or interface destruction), hsr_del_port() is called to

detach the slave port from the HSR master. However, hsr_del_port() currently

does not delete the VLAN IDs that were synced to the slave device by HSR.

As a result, the slave device retains a refcount on VID 0 (and any other

synced VLANs). When the slave device is destroyed, its vlan_info /

vlan_vid_info structure remains allocated, leading to a memory leak.

Fix this by calling vlan_vids_del_by_dev(port->dev, master->dev) in

hsr_del_port() before unlinking slave A or slave B ports, matching the

propagation logic in hsr_ndo_vlan_rx_add_vid() / hsr_ndo_vlan_rx_ki

/// Remediation

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

/// References