{
  "affected": [
    {
      "ranges": [
        {
          "events": [
            {
              "introduced": "fd384412e199b62c3ddaabd18dce86d0e164c5b9"
            },
            {
              "fixed": "dfc96ae0074cc47b5478a59e5aa19233e434243f"
            },
            {
              "fixed": "66117dbb3dbae82f86735bf727b1d59cc677afa1"
            },
            {
              "fixed": "ba7c9ddcdd077942b798979edb035207374d4096"
            },
            {
              "fixed": "a05a2149386f6dfb4245f522acdbef892acafc84"
            },
            {
              "fixed": "9f036aa0fe46c19e938f03d10e02c23f4fffae5e"
            },
            {
              "fixed": "003343985f26dfefd0c94b1fe1316a2de74428b9"
            },
            {
              "fixed": "12aa4b73a67d95bc739995a2d6943aec2f9785c9"
            },
            {
              "fixed": "b3a6df291fecf5f8a308953b65ca72b7fc9e015d"
            }
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "type": "GIT"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "Linux",
        "name": "Kernel"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "3.18.0"
            },
            {
              "fixed": "5.10.253"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "5.11.0"
            },
            {
              "fixed": "5.15.203"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "5.16.0"
            },
            {
              "fixed": "6.1.167"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "6.2.0"
            },
            {
              "fixed": "6.6.130"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "6.7.0"
            },
            {
              "fixed": "6.12.78"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "6.13.0"
            },
            {
              "fixed": "6.18.20"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "6.19.0"
            },
            {
              "fixed": "6.19.10"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "database_specific": {
    "cna_assigner": "Linux",
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/23xxx/CVE-2026-23439.json"
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nudp_tunnel: fix NULL deref caused by udp_sock_create6 when CONFIG_IPV6=n\n\nWhen CONFIG_IPV6 is disabled, the udp_sock_create6() function returns 0\n(success) without actually creating a socket. Callers such as\nfou_create() then proceed to dereference the uninitialized socket\npointer, resulting in a NULL pointer dereference.\n\nThe captured NULL deref crash:\n  BUG: kernel NULL pointer dereference, address: 0000000000000018\n  RIP: 0010:fou_nl_add_doit (net/ipv4/fou_core.c:590 net/ipv4/fou_core.c:764)\n  [...]\n  Call Trace:\n    \u003cTASK\u003e\n    genl_family_rcv_msg_doit.constprop.0 (net/netlink/genetlink.c:1114)\n    genl_rcv_msg (net/netlink/genetlink.c:1194 net/netlink/genetlink.c:1209)\n    [...]\n    netlink_rcv_skb (net/netlink/af_netlink.c:2550)\n    genl_rcv (net/netlink/genetlink.c:1219)\n    netlink_unicast (net/netlink/af_netlink.c:1319 net/netlink/af_netlink.c:1344)\n    netlink_sendmsg (net/netlink/af_netlink.c:1894)\n    __sock_sendmsg (net/socket.c:727 (discriminator 1) net/socket.c:742 (discriminator 1))\n    __sys_sendto (./include/linux/file.h:62 (discriminator 1) ./include/linux/file.h:83 (discriminator 1) net/socket.c:2183 (discriminator 1))\n    __x64_sys_sendto (net/socket.c:2213 (discriminator 1) net/socket.c:2209 (discriminator 1) net/socket.c:2209 (discriminator 1))\n    do_syscall_64 (arch/x86/entry/syscall_64.c:63 (discriminator 1) arch/x86/entry/syscall_64.c:94 (discriminator 1))\n    entry_SYSCALL_64_after_hwframe (net/arch/x86/entry/entry_64.S:130)\n\nThis patch makes udp_sock_create6 return -EPFNOSUPPORT instead, so\ncallers correctly take their error paths. There is only one caller of\nthe vulnerable function and only privileged users can trigger it.",
  "id": "CVE-2026-23439",
  "modified": "2026-07-16T03:31:13.626517094Z",
  "published": "2026-04-03T15:15:23.734Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://cert-portal.siemens.com/productcert/html/ssa-019113.html"
    },
    {
      "type": "WEB",
      "url": "https://cert-portal.siemens.com/productcert/html/ssa-082556.html"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/003343985f26dfefd0c94b1fe1316a2de74428b9"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/12aa4b73a67d95bc739995a2d6943aec2f9785c9"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/66117dbb3dbae82f86735bf727b1d59cc677afa1"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/9f036aa0fe46c19e938f03d10e02c23f4fffae5e"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/a05a2149386f6dfb4245f522acdbef892acafc84"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/b3a6df291fecf5f8a308953b65ca72b7fc9e015d"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/ba7c9ddcdd077942b798979edb035207374d4096"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/dfc96ae0074cc47b5478a59e5aa19233e434243f"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/23xxx/CVE-2026-23439.json"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-23439"
    },
    {
      "type": "PACKAGE",
      "url": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"
    }
  ],
  "schema_version": "1.8.0",
  "summary": "udp_tunnel: fix NULL deref caused by udp_sock_create6 when CONFIG_IPV6=n"
}