GHSA-Q3V2-68CR-QHRM
Vulnerability from github – Published: 2026-07-19 18:31 – Updated: 2026-07-20 15:32In 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().
{
"affected": [],
"aliases": [
"CVE-2026-64123"
],
"database_specific": {
"cwe_ids": [
"CWE-416"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2026-07-19T16:17:53Z",
"severity": "HIGH"
},
"details": "In the Linux kernel, the following vulnerability has been resolved:\n\nnet: hsr: defer node table free until after RCU readers\n\nHSR node-list and node-status generic-netlink operations run under\nrcu_read_lock(). They walk hsr-\u003enode_db through hsr_get_next_node() and\nhsr_get_node_data(), but RTM_DELLINK teardown removes the same node table\nwith plain list_del() and frees each node immediately.\n\nThat lets a generic-netlink reader hold a struct hsr_node pointer across\nhsr_dellink(). In a KASAN build, widening the reader window after\nhsr_get_next_node() obtains the node reproduces a slab-use-after-free\nwhen the reader copies node-\u003emacaddress_A; the freeing stack is\nhsr_del_nodes() from hsr_dellink().\n\nUse list_del_rcu() and defer the free through the existing\nhsr_free_node_rcu() callback. This matches the lifetime rule used by the\nHSR prune paths, which already delete nodes with list_del_rcu() and\ncall_rcu().",
"id": "GHSA-q3v2-68cr-qhrm",
"modified": "2026-07-20T15:32:00Z",
"published": "2026-07-19T18:31:52Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2026-64123"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/0ea70fb46940620848c08d9d399455c9e82fecdb"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/6324423a8e6591f41a16c09a8f9a84e554ac147c"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/7713f4aafb577ff49fa67f0488d9c7dddc64d6ce"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/8be6685cdd1255bcc85f9b59e4bfc313aefc5c1b"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/8c3af18bb0d7c921a5219194037509463eb2ffde"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/aaec7096f9961eb223b5b149abe9495525c205d9"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/c5580114e0492bcd2e0a37613ed4c311e3fa3d4d"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
"type": "CVSS_V3"
}
]
}
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