CVE-2026-68301: net: hsr: fix memory leak on slave unregistration by removing synced VLANs
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 vlanvid0add(), 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), hsrdelport() is called to detach the slave port from the HSR master. However, hsrdelport() 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 vlaninfo / vlanvidinfo structure remains allocated, leading to a memory leak.
Fix this by calling vlanvidsdelbydev(port->dev, master->dev) in hsrdelport() before unlinking slave A or slave B ports, matching the propagation logic in hsrndovlanrxaddvid() / hsrndovlanrxkillvid() and the cleanup behavior in bonding and team drivers.
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Upgrade
Upgrade to a fixed release to a version that resolves this vulnerability.
Patch net: hsr: fix memory leak on slave unregistration by removing synced VLANs
Event History
Frequently Asked Questions
What is the severity of CVE-2026-68301?
The severity of CVE-2026-68301 is rated at 9, indicating a critical risk.
How do I fix CVE-2026-68301?
To fix CVE-2026-68301, update your Linux kernel to the latest version where the memory leak is resolved.
What systems are affected by CVE-2026-68301?
CVE-2026-68301 affects systems running vulnerable versions of the Linux kernel utilizing HSR (High-availability Seamless Redundancy).
What type of vulnerability is CVE-2026-68301?
CVE-2026-68301 is a memory leak vulnerability related to slave device unregistration in the net: hsr module.
When was CVE-2026-68301 published?
CVE-2026-68301 was published on August 10, 2026.