{
  "affected": [
    {
      "ranges": [
        {
          "events": [
            {
              "introduced": "89b768ec2dfefaeba5212de14fc71368e12d06ba"
            },
            {
              "fixed": "5e40919a40cb3e590ed45c2a54a4a2518aa88a99"
            },
            {
              "fixed": "e0c3dd7b30cc5ee42ab502da140cda93d794a20b"
            },
            {
              "fixed": "acab6314bb75be994f720ed13e9d9139cbf828a8"
            },
            {
              "fixed": "979c017803c40829b03acd9e5236e354b7622360"
            }
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "type": "GIT"
        },
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "last_affected": "b3dd82a879f25db9d096ae3053f657aa4260ecc6"
            }
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "type": "GIT"
        },
        {
          "events": [
            {
              "introduced": "6.11.3"
            },
            {
              "fixed": "6.12"
            }
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "type": "GIT"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "Linux",
        "name": "Kernel"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "6.12.0"
            },
            {
              "fixed": "6.12.92"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "6.13.0"
            },
            {
              "fixed": "6.18.34"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "6.19.0"
            },
            {
              "fixed": "7.0.11"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "database_specific": {
    "cna_assigner": "Linux",
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/64xxx/CVE-2026-64119.json"
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nl2tp: use list_del_rcu in l2tp_session_unhash\n\nAn unprivileged local user can pin a host CPU indefinitely in\nl2tp_session_get_by_ifname() by issuing L2TP_CMD_SESSION_GET on\nL2TP_ATTR_IFNAME concurrently with L2TP_CMD_SESSION_CREATE and\nL2TP_CMD_SESSION_DELETE on the same tunnel. All three commands take\nGENL_UNS_ADMIN_PERM, so CAP_NET_ADMIN in the netns user namespace\nsuffices; on any host that has l2tp_core loaded the trigger is\nreachable from a standard `unshare -Urn` sandbox.\n\nl2tp_session_unhash() removes a session from tunnel-\u003esession_list\nwith list_del_init(), but that list is walked by\nl2tp_session_get_by_ifname() with list_for_each_entry_rcu() under\nrcu_read_lock_bh(). list_del_init() leaves the deleted entry's\nnext/prev self-pointing; a reader that has loaded the entry and\nthen advances pos-\u003elist.next reads \u0026session-\u003elist, container_of()s\nback to the same session, and list_for_each_entry_rcu() never\nreaches the list head. The CPU stays in strcmp() inside the\nwalker, with BH and preemption disabled, so RCU grace periods on\nthe host stall behind it and the wedged thread cannot be killed\n(SIGKILL is delivered on syscall return).\n\nUse list_del_rcu() to match the existing list_add_rcu() in\nl2tp_session_register(); the deleted session remains visible to\nin-flight walkers with consistent next/prev pointers until\nkfree_rcu() in l2tp_session_free() releases it. tunnel-\u003esession_list\nhas exactly one list_del_init() call site; the list_del_init\n(\u0026session-\u003eclist) at l2tp_core.c:533 operates on the per-collision\nlist, which is not walked under RCU. list_empty(\u0026session-\u003elist) is\nnot used anywhere in net/l2tp/ after the unhash point, so dropping\nthe post-delete self-init is safe; the fix has no userspace-visible\nbehavior change.",
  "id": "CVE-2026-64119",
  "modified": "2026-07-21T03:42:00.428170914Z",
  "published": "2026-07-19T15:40:18.331Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/5e40919a40cb3e590ed45c2a54a4a2518aa88a99"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/979c017803c40829b03acd9e5236e354b7622360"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/acab6314bb75be994f720ed13e9d9139cbf828a8"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/e0c3dd7b30cc5ee42ab502da140cda93d794a20b"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/64xxx/CVE-2026-64119.json"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-64119"
    },
    {
      "type": "PACKAGE",
      "url": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"
    }
  ],
  "schema_version": "1.8.0",
  "summary": "l2tp: use list_del_rcu in l2tp_session_unhash"
}