{
  "affected": [
    {
      "ecosystem_specific": {
        "urgency": "not yet assigned"
      },
      "package": {
        "ecosystem": "Debian:12",
        "name": "linux"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "6.1.170-1"
            }
          ],
          "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": "6.19.10-1"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "details": "In the Linux kernel, the following vulnerability has been resolved:  udp_tunnel: fix NULL deref caused by udp_sock_create6 when CONFIG_IPV6=n  When CONFIG_IPV6 is disabled, the udp_sock_create6() function returns 0 (success) without actually creating a socket. Callers such as fou_create() then proceed to dereference the uninitialized socket pointer, resulting in a NULL pointer dereference.  The captured NULL deref crash:   BUG: kernel NULL pointer dereference, address: 0000000000000018   RIP: 0010:fou_nl_add_doit (net/ipv4/fou_core.c:590 net/ipv4/fou_core.c:764)   [...]   Call Trace:     \u003cTASK\u003e     genl_family_rcv_msg_doit.constprop.0 (net/netlink/genetlink.c:1114)     genl_rcv_msg (net/netlink/genetlink.c:1194 net/netlink/genetlink.c:1209)     [...]     netlink_rcv_skb (net/netlink/af_netlink.c:2550)     genl_rcv (net/netlink/genetlink.c:1219)     netlink_unicast (net/netlink/af_netlink.c:1319 net/netlink/af_netlink.c:1344)     netlink_sendmsg (net/netlink/af_netlink.c:1894)     __sock_sendmsg (net/socket.c:727 (discriminator 1) net/socket.c:742 (discriminator 1))     __sys_sendto (./include/linux/file.h:62 (discriminator 1) ./include/linux/file.h:83 (discriminator 1) net/socket.c:2183 (discriminator 1))     __x64_sys_sendto (net/socket.c:2213 (discriminator 1) net/socket.c:2209 (discriminator 1) net/socket.c:2209 (discriminator 1))     do_syscall_64 (arch/x86/entry/syscall_64.c:63 (discriminator 1) arch/x86/entry/syscall_64.c:94 (discriminator 1))     entry_SYSCALL_64_after_hwframe (net/arch/x86/entry/entry_64.S:130)  This patch makes udp_sock_create6 return -EPFNOSUPPORT instead, so callers correctly take their error paths. There is only one caller of the vulnerable function and only privileged users can trigger it.",
  "id": "DEBIAN-CVE-2026-23439",
  "modified": "2026-09-14T16:47:49.637832818Z",
  "published": "2026-04-03T16:16:25.737Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://security-tracker.debian.org/tracker/CVE-2026-23439"
    }
  ],
  "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-2026-23439"
  ]
}