GHSA-GXM6-PX42-MPJC

Vulnerability from github – Published: 2026-03-04 15:30 – Updated: 2026-03-17 21:31
VLAI?
Details

In 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.

Severity ?
7.8 (High)
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
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{
  "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": "2026-03-17T21:31:42Z",
  "published": "2026-03-04T15:30:35Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-23231"
    },
    {
      "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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