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

Status: published. Published: 2026-08-10. Updated: 2026-11-06.

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.

## Remediation

No remediation reported in collected sources

## Affected products and versions

- Linux / Linux: ≥ 1100242709d5644856131a9dd25d32672ebe7357; < ccc822e9e4f09a6c2ca73ad5334570441947f94f (affected, git); ≥ a2accc07bdcfb0c7ab2cacdca6a1fe8267816efa; < 79ff0547676acdeceda445c3fce4071b0a887b70 (affected, git); ≥ 72dbae1f2f2159395089405c6c54632f2613f1be; < f72c312af6c7897ab0f8a2b5a63f917a207a4143 (affected, git); ≥ c707d2c5541d2bb94131968ad5dfeb06427a1dba; < 21d48408479a17eb65568a765930adea37e4d804 (affected, git); ≥ 1a8a63a5305e95519de6f941922dfcd8179f82e5; < b5ded444621b6180df9f3d4e07045fc1fc1e8cd9 (affected, git); ≥ 1a8a63a5305e95519de6f941922dfcd8179f82e5; < ae995b8002d3af134560a706c0e111a89e26317c (affected, git); ≥ 1a8a63a5305e95519de6f941922dfcd8179f82e5; < dcf15eaf5641812f1cfc5e96537380132a7da89d (affected, git); ≥ 5.15.194; < 5.15.216 (affected, semver); ≥ 6.1.153; < 6.1.183 (affected, semver); ≥ 6.6.107; < 6.6.148 (affected, semver); ≥ 6.12.48; < 6.12.101 (affected, semver). Source: CNA: Linux
- Linux / Linux: 6.13 (affected); ≥ 0; < 6.13 (unaffected, semver); ≥ 5.15.216; ≤ 5.15.* (unaffected, semver); ≥ 6.1.183; ≤ 6.1.* (unaffected, semver); ≥ 6.6.148; ≤ 6.6.* (unaffected, semver); ≥ 6.12.101; ≤ 6.12.* (unaffected, semver); ≥ 6.18.42; ≤ 6.18.* (unaffected, semver); ≥ 7.1.6; ≤ 7.1.* (unaffected, semver); ≥ 7.2; ≤ * (unaffected, original_commit_for_fix). Source: CNA: Linux

## Severity and prioritization

- CISA KEV: No listing in collected sources

- EPSS: 0.17% as of 2026-11-06; percentile 6.73%

- SSVC: exploitation none; automatable no; technical impact partial; source ADP: CISA-ADP

- Weaknesses: Not reported

## Exploit evidence

No exploit evidence in collected sources. This is not proof of no exploitation.

## References

- https://git.kernel.org/stable/c/ccc822e9e4f09a6c2ca73ad5334570441947f94f (CNA: Linux)

- https://git.kernel.org/stable/c/79ff0547676acdeceda445c3fce4071b0a887b70 (CNA: Linux)

- https://git.kernel.org/stable/c/f72c312af6c7897ab0f8a2b5a63f917a207a4143 (CNA: Linux)

- https://git.kernel.org/stable/c/21d48408479a17eb65568a765930adea37e4d804 (CNA: Linux)

- https://git.kernel.org/stable/c/b5ded444621b6180df9f3d4e07045fc1fc1e8cd9 (CNA: Linux)

- https://git.kernel.org/stable/c/ae995b8002d3af134560a706c0e111a89e26317c (CNA: Linux)

- https://git.kernel.org/stable/c/dcf15eaf5641812f1cfc5e96537380132a7da89d (CNA: Linux)

- https://git.kernel.org/stable/c/21d48408479a17eb65568a765930adea37e4d804 (416baaa9-dc9f-4396-8d5f-8c081fb06d67)

- https://git.kernel.org/stable/c/79ff0547676acdeceda445c3fce4071b0a887b70 (416baaa9-dc9f-4396-8d5f-8c081fb06d67)

- https://git.kernel.org/stable/c/ae995b8002d3af134560a706c0e111a89e26317c (416baaa9-dc9f-4396-8d5f-8c081fb06d67)

- https://git.kernel.org/stable/c/b5ded444621b6180df9f3d4e07045fc1fc1e8cd9 (416baaa9-dc9f-4396-8d5f-8c081fb06d67)

- https://git.kernel.org/stable/c/ccc822e9e4f09a6c2ca73ad5334570441947f94f (416baaa9-dc9f-4396-8d5f-8c081fb06d67)

- https://git.kernel.org/stable/c/dcf15eaf5641812f1cfc5e96537380132a7da89d (416baaa9-dc9f-4396-8d5f-8c081fb06d67)

- https://git.kernel.org/stable/c/f72c312af6c7897ab0f8a2b5a63f917a207a4143 (416baaa9-dc9f-4396-8d5f-8c081fb06d67)

## Provenance

- CNA: Linux: https://www.cve.org/CVERecord?id=CVE-2026-68301; retrieved 2026-11-06; source updated 2026-11-06

- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-68301; retrieved 2026-11-06; source updated 2026-11-06

- FIRST EPSS: https://api.first.org/data/v1/epss?cve=CVE-2026-68301; retrieved 2026-11-06; source updated Not reported

Revision: 639c41954866fbb61437ab8b81b66b1e8c9f8bfd93bd538648007b14b9448e66

Canonical: https://y2.dev/cve/CVE-2026-68301

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