GHSA-GXM6-PX42-MPJC
Vulnerability from github – Published: 2026-03-04 15:30 – Updated: 2026-07-14 15:31In the Linux kernel, the following vulnerability has been resolved:
netfilter: nf_tables: fix use-after-free in nf_tables_addchain()
nf_tables_addchain() publishes the chain to table->chains via list_add_tail_rcu() (in nft_chain_add()) before registering hooks. If nf_tables_register_hook() then fails, the error path calls nft_chain_del() (list_del_rcu()) followed by nf_tables_chain_destroy() with no RCU grace period in between.
This creates two use-after-free conditions:
1) Control-plane: nf_tables_dump_chains() traverses table->chains under rcu_read_lock(). A concurrent dump can still be walking the chain when the error path frees it.
2) Packet path: for NFPROTO_INET, nf_register_net_hook() briefly installs the IPv4 hook before IPv6 registration fails. Packets entering nft_do_chain() via the transient IPv4 hook can still be dereferencing chain->blob_gen_X when the error path frees the chain.
Add synchronize_rcu() between nft_chain_del() and the chain destroy so that all RCU readers -- both dump threads and in-flight packet evaluation -- have finished before the chain is freed.
{
"affected": [],
"aliases": [
"CVE-2026-23231"
],
"database_specific": {
"cwe_ids": [
"CWE-416"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2026-03-04T13:15:58Z",
"severity": "HIGH"
},
"details": "In the Linux kernel, the following vulnerability has been resolved:\n\nnetfilter: nf_tables: fix use-after-free in nf_tables_addchain()\n\nnf_tables_addchain() publishes the chain to table-\u003echains via\nlist_add_tail_rcu() (in nft_chain_add()) before registering hooks.\nIf nf_tables_register_hook() then fails, the error path calls\nnft_chain_del() (list_del_rcu()) followed by nf_tables_chain_destroy()\nwith no RCU grace period in between.\n\nThis creates two use-after-free conditions:\n\n 1) Control-plane: nf_tables_dump_chains() traverses table-\u003echains\n under rcu_read_lock(). A concurrent dump can still be walking\n the chain when the error path frees it.\n\n 2) Packet path: for NFPROTO_INET, nf_register_net_hook() briefly\n installs the IPv4 hook before IPv6 registration fails. Packets\n entering nft_do_chain() via the transient IPv4 hook can still be\n dereferencing chain-\u003eblob_gen_X when the error path frees the\n chain.\n\nAdd synchronize_rcu() between nft_chain_del() and the chain destroy\nso that all RCU readers -- both dump threads and in-flight packet\nevaluation -- have finished before the chain is freed.",
"id": "GHSA-gxm6-px42-mpjc",
"modified": "2026-07-14T15:31:39Z",
"published": "2026-03-04T15:30:35Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2026-23231"
},
{
"type": "WEB",
"url": "https://cert-portal.siemens.com/productcert/html/ssa-019113.html"
},
{
"type": "WEB",
"url": "https://cert-portal.siemens.com/productcert/html/ssa-082556.html"
},
{
"type": "WEB",
"url": "https://cert-portal.siemens.com/productcert/html/ssa-253495.html"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/2a6586ecfa4ce1413daaafee250d2590e05f1a33"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/2f9a4ffeb763aec822f8ff3d1e82202d27d46d4b"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/7017745068a9068904e1e7a1b170a5785647cc81"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/71e99ee20fc3f662555118cf1159443250647533"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/dbd0af8083dd201f07c49110b2ee93710abdff28"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/f3fe58ce37926a10115ede527d59b91bcc05400a"
}
],
"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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