{
  "affected": [
    {
      "ecosystem_specific": {
        "urgency": "not yet assigned"
      },
      "package": {
        "ecosystem": "Debian:12",
        "name": "linux"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "ecosystem_specific": {
        "urgency": "not yet assigned"
      },
      "package": {
        "ecosystem": "Debian:13",
        "name": "linux"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "6.12.85-1"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "ecosystem_specific": {
        "urgency": "not yet assigned"
      },
      "package": {
        "ecosystem": "Debian:14",
        "name": "linux"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "6.19.6-1"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "details": "In the Linux kernel, the following vulnerability has been resolved:  xfrm: always flush state and policy upon NETDEV_UNREGISTER event  syzbot is reporting that \"struct xfrm_state\" refcount is leaking.    unregister_netdevice: waiting for netdevsim0 to become free. Usage count = 2   ref_tracker: netdev@ffff888052f24618 has 1/1 users at        __netdev_tracker_alloc include/linux/netdevice.h:4400 [inline]        netdev_tracker_alloc include/linux/netdevice.h:4412 [inline]        xfrm_dev_state_add+0x3a5/0x1080 net/xfrm/xfrm_device.c:316        xfrm_state_construct net/xfrm/xfrm_user.c:986 [inline]        xfrm_add_sa+0x34ff/0x5fa0 net/xfrm/xfrm_user.c:1022        xfrm_user_rcv_msg+0x58e/0xc00 net/xfrm/xfrm_user.c:3507        netlink_rcv_skb+0x158/0x420 net/netlink/af_netlink.c:2550        xfrm_netlink_rcv+0x71/0x90 net/xfrm/xfrm_user.c:3529        netlink_unicast_kernel net/netlink/af_netlink.c:1318 [inline]        netlink_unicast+0x5aa/0x870 net/netlink/af_netlink.c:1344        netlink_sendmsg+0x8c8/0xdd0 net/netlink/af_netlink.c:1894        sock_sendmsg_nosec net/socket.c:727 [inline]        __sock_sendmsg net/socket.c:742 [inline]        ____sys_sendmsg+0xa5d/0xc30 net/socket.c:2592        ___sys_sendmsg+0x134/0x1d0 net/socket.c:2646        __sys_sendmsg+0x16d/0x220 net/socket.c:2678        do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]        do_syscall_64+0xcd/0xf80 arch/x86/entry/syscall_64.c:94        entry_SYSCALL_64_after_hwframe+0x77/0x7f  This is because commit d77e38e612a0 (\"xfrm: Add an IPsec hardware offloading API\") implemented xfrm_dev_unregister() as no-op despite xfrm_dev_state_add() from xfrm_state_construct() acquires a reference to \"struct net_device\". I guess that that commit expected that NETDEV_DOWN event is fired before NETDEV_UNREGISTER event fires, and also assumed that xfrm_dev_state_add() is called only if (dev-\u003efeatures \u0026 NETIF_F_HW_ESP) != 0.  Sabrina Dubroca identified steps to reproduce the same symptoms as below.    echo 0 \u003e /sys/bus/netdevsim/new_device   dev=$(ls -1 /sys/bus/netdevsim/devices/netdevsim0/net/)   ip xfrm state add src 192.168.13.1 dst 192.168.13.2 proto esp \\      spi 0x1000 mode tunnel aead 'rfc4106(gcm(aes))' $key 128   \\      offload crypto dev $dev dir out   ethtool -K $dev esp-hw-offload off   echo 0 \u003e /sys/bus/netdevsim/del_device  Like these steps indicate, the NETIF_F_HW_ESP bit can be cleared after xfrm_dev_state_add() acquired a reference to \"struct net_device\". Also, xfrm_dev_state_add() does not check for the NETIF_F_HW_ESP bit when acquiring a reference to \"struct net_device\".  Commit 03891f820c21 (\"xfrm: handle NETDEV_UNREGISTER for xfrm device\") re-introduced the NETDEV_UNREGISTER event to xfrm_dev_event(), but that commit for unknown reason chose to share xfrm_dev_down() between the NETDEV_DOWN event and the NETDEV_UNREGISTER event. I guess that that commit missed the behavior in the previous paragraph.  Therefore, we need to re-introduce xfrm_dev_unregister() in order to release the reference to \"struct net_device\" by unconditionally flushing state and policy.",
  "id": "DEBIAN-CVE-2026-43167",
  "modified": "2026-09-14T16:47:50.301728738Z",
  "published": "2026-05-06T12:16:34.913Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://security-tracker.debian.org/tracker/CVE-2026-43167"
    }
  ],
  "severity": [
    {
      "score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H",
      "type": "CVSS_V3"
    }
  ],
  "upstream": [
    "CVE-2026-43167"
  ]
}