{
  "schema_version": "1.6.1",
  "id": "RPI-CVE-2023-53492",
  "modified": "2026-10-09T11:39:44Z",
  "upstream": [
    "CVE-2023-53492"
  ],
  "published": "2025-10-01T11:50:00Z",
  "summary": "netfilter: nf_tables: do not ignore genmask when looking up chain by id",
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nnetfilter: nf_tables: do not ignore genmask when looking up chain by id\n\nWhen adding a rule to a chain referring to its ID, if that chain had been\ndeleted on the same batch, the rule might end up referring to a deleted\nchain.\n\nThis will lead to a WARNING like following:\n\n[   33.098431] ------------[ cut here ]------------\n[   33.098678] WARNING: CPU: 5 PID: 69 at net/netfilter/nf_tables_api.c:2037 nf_tables_chain_destroy+0x23d/0x260\n[   33.099217] Modules linked in:\n[   33.099388] CPU: 5 PID: 69 Comm: kworker/5:1 Not tainted 6.4.0+ #409\n[   33.099726] Workqueue: events nf_tables_trans_destroy_work\n[   33.100018] RIP: 0010:nf_tables_chain_destroy+0x23d/0x260\n[   33.100306] Code: 8b 7c 24 68 e8 64 9c ed fe 4c 89 e7 e8 5c 9c ed fe 48 83 c4 08 5b 41 5c 41 5d 41 5e 41 5f 5d 31 c0 89 c6 89 c7 c3 cc cc cc cc <0f> 0b 48 83 c4 08 5b 41 5c 41 5d 41 5e 41 5f 5d 31 c0 89 c6 89 c7\n[   33.101271] RSP: 0018:ffffc900004ffc48 EFLAGS: 00010202\n[   33.101546] RAX: 0000000000000001 RBX: ffff888006fc0a28 RCX: 0000000000000000\n[   33.101920] RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000\n[   33.102649] RBP: ffffc900004ffc78 R08: 0000000000000000 R09: 0000000000000000\n[   33.103018] R10: 0000000000000000 R11: 0000000000000000 R12: ffff8880135ef500\n[   33.103385] R13: 0000000000000000 R14: dead000000000122 R15: ffff888006fc0a10\n[   33.103762] FS:  0000000000000000(0000) GS:ffff888024c80000(0000) knlGS:0000000000000000\n[   33.104184] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033\n[   33.104493] CR2: 00007fe863b56a50 CR3: 00000000124b0001 CR4: 0000000000770ee0\n[   33.104872] PKRU: 55555554\n[   33.104999] Call Trace:\n[   33.105113]  <TASK>\n[   33.105214]  ? show_regs+0x72/0x90\n[   33.105371]  ? __warn+0xa5/0x210\n[   33.105520]  ? nf_tables_chain_destroy+0x23d/0x260\n[   33.105732]  ? report_bug+0x1f2/0x200\n[   33.105902]  ? handle_bug+0x46/0x90\n[   33.106546]  ? exc_invalid_op+0x19/0x50\n[   33.106762]  ? asm_exc_invalid_op+0x1b/0x20\n[   33.106995]  ? nf_tables_chain_destroy+0x23d/0x260\n[   33.107249]  ? nf_tables_chain_destroy+0x30/0x260\n[   33.107506]  nf_tables_trans_destroy_work+0x669/0x680\n[   33.107782]  ? mark_held_locks+0x28/0xa0\n[   33.107996]  ? __pfx_nf_tables_trans_destroy_work+0x10/0x10\n[   33.108294]  ? _raw_spin_unlock_irq+0x28/0x70\n[   33.108538]  process_one_work+0x68c/0xb70\n[   33.108755]  ? lock_acquire+0x17f/0x420\n[   33.108977]  ? __pfx_process_one_work+0x10/0x10\n[   33.109218]  ? do_raw_spin_lock+0x128/0x1d0\n[   33.109435]  ? _raw_spin_lock_irq+0x71/0x80\n[   33.109634]  worker_thread+0x2bd/0x700\n[   33.109817]  ? __pfx_worker_thread+0x10/0x10\n[   33.110254]  kthread+0x18b/0x1d0\n[   33.110410]  ? __pfx_kthread+0x10/0x10\n[   33.110581]  ret_from_fork+0x29/0x50\n[   33.110757]  </TASK>\n[   33.110866] irq event stamp: 1651\n[   33.111017] hardirqs last  enabled at (1659): [<ffffffffa206a209>] __up_console_sem+0x79/0xa0\n[   33.111379] hardirqs last disabled at (1666): [<ffffffffa206a1ee>] __up_console_sem+0x5e/0xa0\n[   33.111740] softirqs last  enabled at (1616): [<ffffffffa1f5d40e>] __irq_exit_rcu+0x9e/0xe0\n[   33.112094] softirqs last disabled at (1367): [<ffffffffa1f5d40e>] __irq_exit_rcu+0x9e/0xe0\n[   33.112453] ---[ end trace 0000000000000000 ]---\n\nThis is due to the nft_chain_lookup_byid ignoring the genmask. After this\nchange, adding the new rule will fail as it will not find the chain.",
  "severity": [
    {
      "type": "CVSS_V3",
      "score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H"
    }
  ],
  "affected": [
    {
      "package": {
        "ecosystem": "Raspberry Pi OS:12",
        "name": "linux"
      },
      "versions": [
        "1:6.1.21-1+rpt1"
      ],
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "linux-image-6.1.0-rpi1-rpi-v6",
            "binary_version": "1:6.1.21-1+rpt1"
          },
          {
            "binary_name": "linux-image-6.1.0-rpi1-rpi-v7",
            "binary_version": "1:6.1.21-1+rpt1"
          },
          {
            "binary_name": "linux-image-6.1.0-rpi1-rpi-v7l",
            "binary_version": "1:6.1.21-1+rpt1"
          },
          {
            "binary_name": "linux-image-6.1.0-rpi1-rpi-v8",
            "binary_version": "1:6.1.21-1+rpt1"
          }
        ]
      },
      "database_specific": {
        "per_version": {
          "1:6.1.21-1+rpt1": {
            "linux_commit": "0afb5e98488aed7017b9bf321b575d0177feb7ed",
            "upstream_version": "6.1.21",
            "assessment": "commit ancestry (strak rule)",
            "upstream_fixed": "6.1.39"
          }
        }
      }
    }
  ],
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://www.cve.org/CVERecord?id=CVE-2023-53492"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/4ae2e501331aaa506eaf760339bb2f43e5769395"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/041e2ac88caef286b39064e83e825e3f53113d36"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/fc95c8b02c6160936f1f3d8d9d7f4f66f3c84b49"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/5e5e967e8505fbdabfb6497367ec1b808cadc356"
    },
    {
      "type": "FIX",
      "url": "https://git.kernel.org/stable/c/515ad530795c118f012539ed76d02bacfd426d89"
    }
  ],
  "database_specific": {
    "source": "https://git.kernel.org/pub/scm/linux/security/vulns.git",
    "upstream_modified": "2026-08-05T11:24:39Z",
    "severity": {
      "source": "kernel CNA",
      "cvss_v3_score": 7.8,
      "cvss_v3_severity": "High",
      "scenario": "AV:L - nftables is configured through a netlink (NFNL_SUBSYS_NFTABLES) socket handled by nfnetlink_rcv; triggering the bug requires sending a local netlink batch, not remote network traffic.\nAC:L - The attacker crafts a single deterministic batch (NEWCHAIN + DELCHAIN + NEWRULE-by-id) and controls every side of the sequence; there is no race or memory-layout condition outside the attacker's control.\nPR:L - Entry is gated by netlink_net_capable(CAP_NET_ADMIN), which checks the net namespace's user namespace, so an unprivileged user can reach it via unshare -Urn rather than needing real root.\nUI:N - The full exploit is performed by the attacker's own process with no action required from any other user.\nS:U - The corruption stays within the kernel's own security authority, yielding local privilege escalation without crossing a virtualization or IOMMU boundary.\nC:H - A rule retains a dangling reference to a freed chain object; this use-after-free lets the attacker reallocate and read controlled/leaked kernel heap contents, giving high-impact information disclosure.\nI:H - The UAF over nftables chain objects enables heap-spray reallocation and arbitrary write primitives, exploitable for control-flow hijacking and full local privilege escalation.\nA:H - Freeing a chain still referenced by a live rule reliably corrupts kernel memory and panics/oopses the kernel, causing denial of service."
    }
  }
}