{
  "affected": [
    {
      "ranges": [
        {
          "events": [
            {
              "introduced": "58c9b016e12855286370dfb704c08498edbc857a"
            },
            {
              "fixed": "2de4db145b2992da496fea6c51f9839be678ae24"
            },
            {
              "fixed": "9324de74a3a59b9fde9b62ee45ebaa71458ba2e5"
            },
            {
              "fixed": "ef4ca02e95363e78977ca04340d44fe3b4b2b81f"
            },
            {
              "fixed": "ced39b6a8062bac5c18a1c3df85634107eb8664a"
            },
            {
              "fixed": "a6dc643c69311677c574a0f17a3f4d66a5f3744b"
            }
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "type": "GIT"
        },
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "last_affected": "f2451def095c1743adcfcb0cb5dadc86034e162a"
            },
            {
              "last_affected": "a1f93804449d13f97dabd4b996817de4bf1ed67a"
            }
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "type": "GIT"
        },
        {
          "events": [
            {
              "introduced": "5.15.209"
            },
            {
              "fixed": "5.16"
            }
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "type": "GIT"
        },
        {
          "events": [
            {
              "introduced": "6.1.175"
            },
            {
              "fixed": "6.2"
            }
          ],
          "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": "6.6.144"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "6.7.0"
            },
            {
              "fixed": "6.12.95"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "6.13.0"
            },
            {
              "fixed": "6.18.33"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "6.19.0"
            },
            {
              "fixed": "7.0.10"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "database_specific": {
    "cna_assigner": "Linux",
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/46xxx/CVE-2026-46242.json"
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\neventpoll: fix ep_remove struct eventpoll / struct file UAF\n\nep_remove() (via ep_remove_file()) cleared file-\u003ef_ep under\nfile-\u003ef_lock but then kept using @file inside the critical section\n(is_file_epoll(), hlist_del_rcu() through the head, spin_unlock).\nA concurrent __fput() taking the eventpoll_release() fastpath in\nthat window observed the transient NULL, skipped\neventpoll_release_file() and ran to f_op-\u003erelease / file_free().\n\nFor the epoll-watches-epoll case, f_op-\u003erelease is\nep_eventpoll_release() -\u003e ep_clear_and_put() -\u003e ep_free(), which\nkfree()s the watched struct eventpoll. Its embedded -\u003erefs\nhlist_head is exactly where epi-\u003efllink.pprev points, so the\nsubsequent hlist_del_rcu()'s \"*pprev = next\" scribbles into freed\nkmalloc-192 memory.\n\nIn addition, struct file is SLAB_TYPESAFE_BY_RCU, so the slot\nbacking @file could be recycled by alloc_empty_file() --\nreinitializing f_lock and f_ep -- while ep_remove() is still\nnominally inside that lock. The upshot is an attacker-controllable\nkmem_cache_free() against the wrong slab cache.\n\nPin @file via epi_fget() at the top of ep_remove() and gate the\ncritical section on the pin succeeding. With the pin held @file\ncannot reach refcount zero, which holds __fput() off and\ntransitively keeps the watched struct eventpoll alive across the\nhlist_del_rcu() and the f_lock use, closing both UAFs.\n\nIf the pin fails @file has already reached refcount zero and its\n__fput() is in flight. Because we bailed before clearing f_ep,\nthat path takes the eventpoll_release() slow path into\neventpoll_release_file() and blocks on ep-\u003emtx until the waiter\nside's ep_clear_and_put() drops it. The bailed epi's share of\nep-\u003erefcount stays intact, so the trailing ep_refcount_dec_and_test()\nin ep_clear_and_put() cannot free the eventpoll out from under\neventpoll_release_file(); the orphaned epi is then cleaned up\nthere.\n\nA successful pin also proves we are not racing\neventpoll_release_file() on this epi, so drop the now-redundant\nre-check of epi-\u003edying under f_lock. The cheap lockless\nREAD_ONCE(epi-\u003edying) fast-path bailout stays.",
  "id": "CVE-2026-46242",
  "modified": "2026-07-10T03:53:55.814384614Z",
  "published": "2026-05-30T12:13:45.594Z",
  "references": [
    {
      "type": "WEB",
      "url": "http://www.openwall.com/lists/oss-security/2026/07/08/14"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/2de4db145b2992da496fea6c51f9839be678ae24"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/9324de74a3a59b9fde9b62ee45ebaa71458ba2e5"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/a6dc643c69311677c574a0f17a3f4d66a5f3744b"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/ced39b6a8062bac5c18a1c3df85634107eb8664a"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/ef4ca02e95363e78977ca04340d44fe3b4b2b81f"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/46xxx/CVE-2026-46242.json"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-46242"
    },
    {
      "type": "PACKAGE",
      "url": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"
    }
  ],
  "schema_version": "1.7.5",
  "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": "eventpoll: fix ep_remove struct eventpoll / struct file UAF"
}