CVE-2026-64123

/// Technical description

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

net: hsr: defer node table free until after RCU readers

HSR node-list and node-status generic-netlink operations run under

rcu_read_lock(). They walk hsr->node_db through hsr_get_next_node() and

hsr_get_node_data(), but RTM_DELLINK teardown removes the same node table

with plain list_del() and frees each node immediately.

That lets a generic-netlink reader hold a struct hsr_node pointer across

hsr_dellink(). In a KASAN build, widening the reader window after

hsr_get_next_node() obtains the node reproduces a slab-use-after-free

when the reader copies node->macaddress_A; the freeing stack is

hsr_del_nodes() from hsr_dellink().

Use list_del_rcu() and defer the free through the existing

hsr_free_node_rcu() callback. This matches the lifetime rule used by the

HSR prune paths, which already delete nodes with list_del_rcu() and

call_rcu().

/// 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