{
  "affected": [
    {
      "ranges": [
        {
          "events": [
            {
              "introduced": "7235759084a4f8524a46bd2638885ff3b34ce279"
            },
            {
              "fixed": "25acb6711da6fa0382744fa92bd6d42a22c1ae68"
            },
            {
              "fixed": "95400e7039cdfeb0b53652d521d766f1698cae95"
            },
            {
              "fixed": "b33ac2d39953efb12f598c0dae242c5f644ea669"
            },
            {
              "fixed": "05b24f68f78ff3a1ef7f015f7327b35886b741f6"
            },
            {
              "fixed": "50fd6dd755c6e48a38af2fa4621167eea56829c2"
            }
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "type": "GIT"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "Linux",
        "name": "Kernel"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "6.4.0"
            },
            {
              "fixed": "6.6.148"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "6.7.0"
            },
            {
              "fixed": "6.12.97"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "6.13.0"
            },
            {
              "fixed": "6.18.40"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "6.19.0"
            },
            {
              "fixed": "7.1.5"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "database_specific": {
    "cna_assigner": "Linux",
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/72xxx/CVE-2026-72071.json"
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\ntracing/user_events: Fix use-after-free in user_event_mm_dup()\n\nuser_event_mm_dup() walks the parent mm's enabler list locklessly under\nrcu_read_lock() during fork() (from copy_process()); it does not take\nevent_mutex:\n\n\trcu_read_lock();\n\tlist_for_each_entry_rcu(enabler, \u0026old_mm-\u003eenablers, mm_enablers_link)\n\t\tenabler-\u003eevent = user_event_get(orig-\u003eevent);\n\nuser_event_enabler_destroy() removes an enabler from that list with\nlist_del_rcu() and then, without waiting for a grace period, drops the\nenabler's user_event reference with user_event_put() and frees the enabler\nwith kfree(). A reader that loaded the enabler before the list_del_rcu()\ncan still be walking it, which leads to two use-after-frees:\n\n - kfree(enabler) frees the enabler while that reader dereferences\n   enabler-\u003eevent.\n\n - user_event_put() may drop the last reference to the user_event, which\n   is then freed (via delayed_destroy_user_event() on a work queue), while\n   the same reader does user_event_get(orig-\u003eevent) on it.\n\nBoth are reachable by an unprivileged task that can open user_events_data:\none multithreaded process that registers an enabler and then concurrently\nunregisters it and calls fork() triggers the race. KASAN reports a\nslab-use-after-free in user_event_mm_dup() during clone(), with a\n\"refcount_t: addition on 0\" warning when the user_event is freed.\n\nThe enabler use-after-free was found first; the user_event one was reported\nby XIAO WU, and the earlier enabler-only fix did not address it.\n\nDefer both the user_event_put() and the kfree(enabler) to a work item\nqueued with queue_rcu_work(), so they run only after an RCU grace period,\nonce all readers walking the enabler list have finished. The put must run\nin process context because user_event_put() takes event_mutex on the last\nreference, so a work queue is used rather than call_rcu(). The now-unlocked\nput lets the locked argument of user_event_enabler_destroy() be removed;\nall callers are updated.",
  "id": "CVE-2026-72071",
  "modified": "2026-08-18T03:31:10.826176215Z",
  "published": "2026-08-15T05:52:23.215Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/05b24f68f78ff3a1ef7f015f7327b35886b741f6"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/25acb6711da6fa0382744fa92bd6d42a22c1ae68"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/50fd6dd755c6e48a38af2fa4621167eea56829c2"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/95400e7039cdfeb0b53652d521d766f1698cae95"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/b33ac2d39953efb12f598c0dae242c5f644ea669"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/72xxx/CVE-2026-72071.json"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-72071"
    },
    {
      "type": "PACKAGE",
      "url": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"
    }
  ],
  "schema_version": "1.9.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
      "type": "CVSS_V3"
    }
  ],
  "summary": "tracing/user_events: Fix use-after-free in user_event_mm_dup()"
}