GHSA-GQGJ-WW6J-QXJ3
Vulnerability from github – Published: 2026-09-25 12:31 – Updated: 2026-09-25 15:31In the Linux kernel, the following vulnerability has been resolved:
netfilter: nf_log: unregister loggers before per-net teardown
nf_log_syslog and nfnetlink_log unregister their per-network namespace operations before unregistering their global logger backends. This leaves a window where a sysctl or netlink writer can rebind the still- registered logger after the per-net pre-exit callback cleared the old selection.
The race looks like this:
CPU 0 CPU 1 ---- ---- unregister_pernet_subsys() nf_log_unset(net, logger) net->nf.nf_loggers[pf] = NULL
lock nf_log_mutex
find logger in loggers[][]
net->nf.nf_loggers[pf] = logger
unlock nf_log_mutex
nf_log_unregister(logger) lock nf_log_mutex loggers[pf][type] = NULL unlock nf_log_mutex synchronize_rcu() module exit returns module core frees backend memory
Later, a sysctl read or packet logging operation can dereference the stale per-net logger pointer.
Fix this by unregistering the global logger backends before tearing down per-net state. Once the global registrations are gone, later writers can no longer rebind the logger. unregister_pernet_subsys() already waits for an RCU grace period after the pre-exit callback clears the per-net selection, while nf_log_unregister() continues to cover readers of the global logger table.
Apply this ordering fix to both nf_log backends that combine per-net teardown with global logger registration.
{
"affected": [],
"aliases": [
"CVE-2026-97608"
],
"database_specific": {
"cwe_ids": [],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2026-09-25T11:17:14Z",
"severity": "HIGH"
},
"details": "In the Linux kernel, the following vulnerability has been resolved:\n\nnetfilter: nf_log: unregister loggers before per-net teardown\n\nnf_log_syslog and nfnetlink_log unregister their per-network namespace\noperations before unregistering their global logger backends. This\nleaves a window where a sysctl or netlink writer can rebind the still-\nregistered logger after the per-net pre-exit callback cleared the old\nselection.\n\nThe race looks like this:\n\n CPU 0 CPU 1\n ---- ----\n unregister_pernet_subsys()\n nf_log_unset(net, logger)\n net-\u003enf.nf_loggers[pf] = NULL\n\n lock nf_log_mutex\n find logger in loggers[][]\n net-\u003enf.nf_loggers[pf] = logger\n unlock nf_log_mutex\n\n nf_log_unregister(logger)\n lock nf_log_mutex\n loggers[pf][type] = NULL\n unlock nf_log_mutex\n synchronize_rcu()\n module exit returns\n module core frees backend memory\n\nLater, a sysctl read or packet logging operation can dereference the\nstale per-net logger pointer.\n\nFix this by unregistering the global logger backends before tearing down\nper-net state. Once the global registrations are gone, later writers can\nno longer rebind the logger. unregister_pernet_subsys() already waits\nfor an RCU grace period after the pre-exit callback clears the per-net\nselection, while nf_log_unregister() continues to cover readers of the\nglobal logger table.\n\nApply this ordering fix to both nf_log backends that combine per-net\nteardown with global logger registration.",
"id": "GHSA-gqgj-ww6j-qxj3",
"modified": "2026-09-25T15:31:43Z",
"published": "2026-09-25T12:31:26Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2026-97608"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/2c018cc4842c33f0c732962e2ab58635e8ae5823"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/64803ba0a05791cf9ca874466480e4c4cadaf7ab"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/dce24f3a146948595bb1b86347f31e20b4975daa"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/eaec35fae8f2052c1878a5c7cc7699d8357d79f2"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H",
"type": "CVSS_V3"
}
]
}
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