{
  "cveId": "CVE-2021-47222",
  "url": "https://patchblox.com/security/cve/CVE-2021-47222",
  "summary": "CVE-2021-47222 is fixed in linux on 1 platform, first by DEBIAN-CVE-2021-47222, released May 21, 2024. It is not reported as exploited. Patch Radar priority: High.",
  "title": "linux: In the Linux kernel, the following vulnerability has been resolved:  net: bridge: fix vlan tunnel dst refcnt when egr...",
  "description": "In the Linux kernel, the following vulnerability has been resolved:  net: bridge: fix vlan tunnel dst refcnt when egressing  The egress tunnel code uses dst_clone() and directly sets the result which is wrong because the entry might have 0 refcnt or be already deleted, causing number of problems. It also triggers the WARN_ON() in dst_hold()[1] when a refcnt couldn\u0027t be taken. Fix it by using dst_hold_safe() and checking if a reference was actually taken before setting the dst.  [1] dmesg WARN_ON log and following refcnt errors  WARNING: CPU: 5 PID: 38 at include/net/dst.h:230 br_handle_egress_vlan_tunnel\u002B0x10b/0x134 [bridge]  Modules linked in: 8021q garp mrp bridge stp llc bonding ipv6 virtio_net  CPU: 5 PID: 38 Comm: ksoftirqd/5 Kdump: loaded Tainted: G        W         5.13.0-rc3\u002B #360  Hardware name: QEMU Standard PC (i440FX \u002B PIIX, 1996), BIOS 1.14.0-1.fc33 04/01/2014  RIP: 0010:br_handle_egress_vlan_tunnel\u002B0x10b/0x134 [bridge]  Code: e8 85 bc 01 e1 45 84 f6 74 90 45 31 f6 85 db 48 c7 c7 a0 02 19 a0 41 0f 94 c6 31 c9 31 d2 44 89 f6 e8 64 bc 01 e1 85 db 75 02 \u003C0f\u003E 0b 31 c9 31 d2 44 89 f6 48 c7 c7 70 02 19 a0 e8 4b bc 01 e1 49  RSP: 0018:ffff8881003d39e8 EFLAGS: 00010246  RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000  RDX: 0000000000000000 RSI: 0000000000000001 RDI: ffffffffa01902a0  RBP: ffff8881040c6700 R08: 0000000000000000 R09: 0000000000000001  R10: 2ce93d0054fe0d00 R11: 54fe0d00000e0000 R12: ffff888109515000  R13: 0000000000000000 R14: 0000000000000001 R15: 0000000000000401  FS:  0000000000000000(0000) GS:ffff88822bf40000(0000) knlGS:0000000000000000  CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033  CR2: 00007f42ba70f030 CR3: 0000000109926000 CR4: 00000000000006e0  Call Trace:   br_handle_vlan\u002B0xbc/0xca [bridge]   __br_forward\u002B0x23/0x164 [bridge]   deliver_clone\u002B0x41/0x48 [bridge]   br_handle_frame_finish\u002B0x36f/0x3aa [bridge]   ? skb_dst\u002B0x2e/0x38 [bridge]   ? br_handle_ingress_vlan_tunnel\u002B0x3e/0x1c8 [bridge]   ? br_handle_frame_finish\u002B0x3aa/0x3aa [bridge]   br_handle_frame\u002B0x2c3/0x377 [bridge]   ? __skb_pull\u002B0x33/0x51   ? vlan_do_receive\u002B0x4f/0x36a   ? br_handle_frame_finish\u002B0x3aa/0x3aa [bridge]   __netif_receive_skb_core\u002B0x539/0x7c6   ? __list_del_entry_valid\u002B0x16e/0x1c2   __netif_receive_skb_list_core\u002B0x6d/0xd6   netif_receive_skb_list_internal\u002B0x1d9/0x1fa   gro_normal_list\u002B0x22/0x3e   dev_gro_receive\u002B0x55b/0x600   ? detach_buf_split\u002B0x58/0x140   napi_gro_receive\u002B0x94/0x12e   virtnet_poll\u002B0x15d/0x315 [virtio_net]   __napi_poll\u002B0x2c/0x1c9   net_rx_action\u002B0xe6/0x1fb   __do_softirq\u002B0x115/0x2d8   run_ksoftirqd\u002B0x18/0x20   smpboot_thread_fn\u002B0x183/0x19c   ? smpboot_unregister_percpu_thread\u002B0x66/0x66   kthread\u002B0x10a/0x10f   ? kthread_mod_delayed_work\u002B0xb6/0xb6   ret_from_fork\u002B0x22/0x30  ---[ end trace 49f61b07f775fd2b ]---  dst_release: dst:00000000c02d677a refcnt:-1  dst_release underflow",
  "published": "2024-05-21T15:15:11Z",
  "severity": "high",
  "cvss": 7.8,
  "cvssVector": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
  "epss": 0.00248,
  "epssPercentile": 0.16162,
  "priority": "High",
  "priorityTier": 3,
  "exploited": false,
  "vendorExploited": false,
  "disclosed": false,
  "fixes": [
    {
      "platform": "linux",
      "product": "linux",
      "release": "Debian 12.15 (bookworm)",
      "fixedVersion": "5.10.46-1",
      "fix": "DEBIAN-CVE-2021-47222",
      "url": "https://patchblox.com/security/fix/linux/debian-cve-2021-47222",
      "released": "2024-05-21T15:15:11Z"
    },
    {
      "platform": "linux",
      "product": "linux",
      "release": "Debian 13.5 (trixie)",
      "fixedVersion": "5.10.46-1",
      "fix": "DEBIAN-CVE-2021-47222",
      "url": "https://patchblox.com/security/fix/linux/debian-cve-2021-47222",
      "released": "2024-05-21T15:15:11Z"
    },
    {
      "platform": "linux",
      "product": "linux",
      "release": "Debian 14",
      "fixedVersion": "5.10.46-1",
      "fix": "DEBIAN-CVE-2021-47222",
      "url": "https://patchblox.com/security/fix/linux/debian-cve-2021-47222",
      "released": "2024-05-21T15:15:11Z"
    }
  ],
  "noFixYet": [],
  "dataAsOf": "2026-11-09T01:18:40Z",
  "attribution": {
    "text": "Data: Patchblox Patch Radar",
    "url": "https://patchblox.com/security/patch-radar",
    "terms": "https://patchblox.com/security/patch-radar/use-the-data"
  }
}