CVE-2026-46259 (GCVE-0-2026-46259)
Vulnerability from cvelistv5
Published
2026-06-03 15:49
Modified
2026-08-05 12:30
Summary
In the Linux kernel, the following vulnerability has been resolved: procfs: fix missing RCU protection when reading real_parent in do_task_stat() When reading /proc/[pid]/stat, do_task_stat() accesses task->real_parent without proper RCU protection, which leads to: cpu 0 cpu 1 ----- ----- do_task_stat var = task->real_parent release_task call_rcu(delayed_put_task_struct) task_tgid_nr_ns(var) rcu_read_lock <--- Too late to protect task->real_parent! task_pid_ptr <--- UAF! rcu_read_unlock This patch uses task_ppid_nr_ns() instead of task_tgid_nr_ns() to add proper RCU protection for accessing task->real_parent.
Impacted products
Vendor Product Version
Linux Linux Version: 06fffb1267c9d986687b69d74a46ee332a50575e
Version: 06fffb1267c9d986687b69d74a46ee332a50575e
Version: 06fffb1267c9d986687b69d74a46ee332a50575e
Version: 06fffb1267c9d986687b69d74a46ee332a50575e
Version: 06fffb1267c9d986687b69d74a46ee332a50575e
Version: 06fffb1267c9d986687b69d74a46ee332a50575e
Version: 06fffb1267c9d986687b69d74a46ee332a50575e
Version: 06fffb1267c9d986687b69d74a46ee332a50575e
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{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "fs/proc/array.c"
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          "vendor": "Linux",
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              "version": "2.6.26"
            },
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              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "5.10.*",
              "status": "unaffected",
              "version": "5.10.252",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "5.15.*",
              "status": "unaffected",
              "version": "5.15.202",
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            },
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              "lessThanOrEqual": "6.1.*",
              "status": "unaffected",
              "version": "6.1.165",
              "versionType": "semver"
            },
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              "status": "unaffected",
              "version": "6.6.128",
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              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.75",
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            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.14",
              "versionType": "semver"
            },
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              "lessThanOrEqual": "6.19.*",
              "status": "unaffected",
              "version": "6.19.4",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.0",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
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                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "5.10.252",
                  "versionStartIncluding": "2.6.26",
                  "vulnerable": true
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                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
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                  "vulnerable": true
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                {
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                  "versionEndExcluding": "7.0",
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                  "vulnerable": true
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              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nprocfs: fix missing RCU protection when reading real_parent in do_task_stat()\n\nWhen reading /proc/[pid]/stat, do_task_stat() accesses task-\u003ereal_parent\nwithout proper RCU protection, which leads to:\n\n  cpu 0                               cpu 1\n  -----                               -----\n  do_task_stat\n    var = task-\u003ereal_parent\n                                      release_task\n                                        call_rcu(delayed_put_task_struct)\n    task_tgid_nr_ns(var)\n      rcu_read_lock   \u003c--- Too late to protect task-\u003ereal_parent!\n      task_pid_ptr    \u003c--- UAF!\n      rcu_read_unlock\n\nThis patch uses task_ppid_nr_ns() instead of task_tgid_nr_ns() to add\nproper RCU protection for accessing task-\u003ereal_parent."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "baseScore": 7.8,
            "baseSeverity": "HIGH",
            "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
            "version": "3.1"
          },
          "scenarios": [
            {
              "lang": "en",
              "value": "AV:L - Exploitation requires local `open()`/`read()` on procfs (`/proc/[pid]/stat` or thread `stat`); there is no network, adjacent-radio, or physical-device path to `do_task_stat()`.\nAC:L - An attacker can reliably race by running concurrent `read()` loops on `/proc/child/stat` while another thread exits and reaps the parent via `wait4()`, controlling both sides of the `release_task()`/`call_rcu()` window.\nPR:L - Triggering the bug needs only an unprivileged local account that can read procfs (default `hidepid=off` allows reading other users\u2019 `stat`); no real root or init-namespace-only capability is required.\nUI:N - Exploitation is fully attacker-driven through syscalls and process lifecycle control; no victim user action (clicks, mounts, etc.) is needed.\nS:U - Impact is confined to kernel memory corruption and privilege escalation within the same kernel security domain, not a cross-boundary escape such as VM guest-to-host.\nC:H - The UAF dereferences freed `task_struct` memory via `task_pid_ptr()`/`__task_pid_nr_ns()`, enabling disclosure of stale slab contents and kernel pointers that can be groomed into an arbitrary-read primitive.\nI:H - Use-after-free on a `task_struct` slab object can be leveraged with heap grooming for control of freed memory and potential arbitrary write or code execution, not merely a bounded or cosmetic change.\nA:H - Concurrent UAF access to a freed parent `task_struct` can cause kernel oops/panic (KASAN reports slab-use-after-free class failures) even when full exploitation is not attempted."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-08-05T12:30:48.120Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/fefa0fcd78be465b7ad4c497fa6ec90d64194c04"
        },
        {
          "url": "https://git.kernel.org/stable/c/c93a33f28f915d446eea6fb3f0e1def0b3af1982"
        },
        {
          "url": "https://git.kernel.org/stable/c/1c8dc5b5517546c68ffae40b948336122bb61306"
        },
        {
          "url": "https://git.kernel.org/stable/c/0e64bd46a04a4fd61279aca9f53a664e9e5f7e7e"
        },
        {
          "url": "https://git.kernel.org/stable/c/73ec7c96601d61d52310c659145bb06d933a0fa6"
        },
        {
          "url": "https://git.kernel.org/stable/c/4f9ae386861e280b7631ca252f798d25575627ee"
        },
        {
          "url": "https://git.kernel.org/stable/c/dd8b13cb4ff1a4545a214ed897fdf2bc341155b6"
        },
        {
          "url": "https://git.kernel.org/stable/c/76149d53502cf17ef3ae454ff384551236fba867"
        }
      ],
      "title": "procfs: fix missing RCU protection when reading real_parent in do_task_stat()",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-46259",
    "datePublished": "2026-06-03T15:49:56.428Z",
    "dateReserved": "2026-05-13T15:03:33.108Z",
    "dateUpdated": "2026-08-05T12:30:48.120Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}


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