# CVE-2026-68301: net: hsr: fix memory leak on slave unregistration by removing synced VLANs

> A memory leak in the Linux kernel HSR driver allows local attackers to cause denial of service by triggering slave device unregistration.

- **Severity:** Not scored
- **Exploited in the wild:** Not known
- **Login needed:** An administrator
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 10 Aug 2026
- **Updated:** 19 Aug 2026
- **Also known as:** BELL-CVE-2026-68301, DEBIAN-CVE-2026-68301, GHSA-f9h5-hhgx-wh5m, UBUNTU-CVE-2026-68301

## What is CVE-2026-68301?

CVE-2026-68301 is a memory corruption vulnerability in Linux, published on 10 Aug 2026. 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: 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_kill_vid()
and the cleanup behavior in bonding and team drivers.

## Which versions are affected by CVE-2026-68301?


## How do I fix CVE-2026-68301?

Apply the vendor's patch.

## Is CVE-2026-68301 being exploited?

There is no known exploitation of CVE-2026-68301 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-68301 and fix it if it is affected.

What it is: CVE-2026-68301 is a memory corruption vulnerability in Linux, published on 10 Aug 2026. 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-2026-68301 in the wild and no public exploit code.

Affected product: Linux. 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-2026-68301/ (Markdown: https://insights.sbomify.com/CVE-2026-68301/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-68301
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-68301
- OSV: https://osv.dev/vulnerability/CVE-2026-68301

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-68301/
Summaries are generated and may contain mistakes; the official description above is the record.