Vulnerability-Lookup

FKIE_CVE-2021-47069

Vulnerability from fkie_nvd - Published: 2024-03-01 22:15 - Updated: 2026-08-04 10:16

Severity

7.8 (High) - CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
7.0 (High) - CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H

Summary

In the Linux kernel, the following vulnerability has been resolved: ipc/mqueue, msg, sem: avoid relying on a stack reference past its expiry do_mq_timedreceive calls wq_sleep with a stack local address. The sender (do_mq_timedsend) uses this address to later call pipelined_send. This leads to a very hard to trigger race where a do_mq_timedreceive call might return and leave do_mq_timedsend to rely on an invalid address, causing the following crash: RIP: 0010:wake_q_add_safe+0x13/0x60 Call Trace: __x64_sys_mq_timedsend+0x2a9/0x490 do_syscall_64+0x80/0x680 entry_SYSCALL_64_after_hwframe+0x44/0xa9 RIP: 0033:0x7f5928e40343 The race occurs as: 1. do_mq_timedreceive calls wq_sleep with the address of `struct ext_wait_queue` on function stack (aliased as `ewq_addr` here) - it holds a valid `struct ext_wait_queue *` as long as the stack has not been overwritten. 2. `ewq_addr` gets added to info->e_wait_q[RECV].list in wq_add, and do_mq_timedsend receives it via wq_get_first_waiter(info, RECV) to call __pipelined_op. 3. Sender calls __pipelined_op::smp_store_release(&this->state, STATE_READY). Here is where the race window begins. (`this` is `ewq_addr`.) 4. If the receiver wakes up now in do_mq_timedreceive::wq_sleep, it will see `state == STATE_READY` and break. 5. do_mq_timedreceive returns, and `ewq_addr` is no longer guaranteed to be a `struct ext_wait_queue *` since it was on do_mq_timedreceive's stack. (Although the address may not get overwritten until another function happens to touch it, which means it can persist around for an indefinite time.) 6. do_mq_timedsend::__pipelined_op() still believes `ewq_addr` is a `struct ext_wait_queue *`, and uses it to find a task_struct to pass to the wake_q_add_safe call. In the lucky case where nothing has overwritten `ewq_addr` yet, `ewq_addr->task` is the right task_struct. In the unlucky case, __pipelined_op::wake_q_add_safe gets handed a bogus address as the receiver's task_struct causing the crash. do_mq_timedsend::__pipelined_op() should not dereference `this` after setting STATE_READY, as the receiver counterpart is now free to return. Change __pipelined_op to call wake_q_add_safe on the receiver's task_struct returned by get_task_struct, instead of dereferencing `this` which sits on the receiver's stack. As Manfred pointed out, the race potentially also exists in ipc/msg.c::expunge_all and ipc/sem.c::wake_up_sem_queue_prepare. Fix those in the same way.

References

URL	Tags
416baaa9-dc9f-4396-8d5f-8c081fb06d67	https://git.kernel.org/stable/c/4528c0c323085e645b8765913b4a7fd42cf49b65	Patch
416baaa9-dc9f-4396-8d5f-8c081fb06d67	https://git.kernel.org/stable/c/807fa14536b26803b858da878b643be72952a097	Patch
416baaa9-dc9f-4396-8d5f-8c081fb06d67	https://git.kernel.org/stable/c/a11ddb37bf367e6b5239b95ca759e5389bb46048	Patch
af854a3a-2127-422b-91ae-364da2661108	https://git.kernel.org/stable/c/4528c0c323085e645b8765913b4a7fd42cf49b65	Patch
af854a3a-2127-422b-91ae-364da2661108	https://git.kernel.org/stable/c/807fa14536b26803b858da878b643be72952a097	Patch
af854a3a-2127-422b-91ae-364da2661108	https://git.kernel.org/stable/c/a11ddb37bf367e6b5239b95ca759e5389bb46048	Patch

Impacted products

Vendor	Product	Version
linux	linux_kernel	*
linux	linux_kernel	*
linux	linux_kernel	5.13
linux	linux_kernel	5.13

JSON

To clipboard

{
  "affected": [
    {
      "affectedData": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "ipc/mqueue.c",
            "ipc/msg.c",
            "ipc/sem.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "4528c0c323085e645b8765913b4a7fd42cf49b65",
              "status": "affected",
              "version": "c5b2cbdbdac563f46ecd5e187253ab1abbd6fc04",
              "versionType": "git"
            },
            {
              "lessThan": "807fa14536b26803b858da878b643be72952a097",
              "status": "affected",
              "version": "c5b2cbdbdac563f46ecd5e187253ab1abbd6fc04",
              "versionType": "git"
            },
            {
              "lessThan": "a11ddb37bf367e6b5239b95ca759e5389bb46048",
              "status": "affected",
              "version": "c5b2cbdbdac563f46ecd5e187253ab1abbd6fc04",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "ipc/mqueue.c",
            "ipc/msg.c",
            "ipc/sem.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "5.6"
            },
            {
              "lessThan": "5.6",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "5.10.*",
              "status": "unaffected",
              "version": "5.10.40",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "5.12.*",
              "status": "unaffected",
              "version": "5.12.7",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "5.13",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    }
  ],
  "configurations": [
    {
      "nodes": [
        {
          "cpeMatch": [
            {
              "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
              "matchCriteriaId": "CC04C860-B3F3-4630-B20D-99BEA8F2A42A",
              "versionEndExcluding": "5.10.40",
              "versionStartIncluding": "5.6",
              "vulnerable": true
            },
            {
              "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
              "matchCriteriaId": "E8F2CE30-38B0-4716-B12B-A139B0F9C5C9",
              "versionEndExcluding": "5.12.7",
              "versionStartIncluding": "5.11",
              "vulnerable": true
            },
            {
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              "matchCriteriaId": "0CBAD0FC-C281-4666-AB2F-F8E6E1165DF7",
              "vulnerable": true
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              "matchCriteriaId": "96AC23B2-D46A-49D9-8203-8E1BEDCA8532",
              "vulnerable": true
            }
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          "negate": false,
          "operator": "OR"
        }
      ]
    }
  ],
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nipc/mqueue, msg, sem: avoid relying on a stack reference past its expiry\n\ndo_mq_timedreceive calls wq_sleep with a stack local address.  The\nsender (do_mq_timedsend) uses this address to later call pipelined_send.\n\nThis leads to a very hard to trigger race where a do_mq_timedreceive\ncall might return and leave do_mq_timedsend to rely on an invalid\naddress, causing the following crash:\n\n  RIP: 0010:wake_q_add_safe+0x13/0x60\n  Call Trace:\n   __x64_sys_mq_timedsend+0x2a9/0x490\n   do_syscall_64+0x80/0x680\n   entry_SYSCALL_64_after_hwframe+0x44/0xa9\n  RIP: 0033:0x7f5928e40343\n\nThe race occurs as:\n\n1. do_mq_timedreceive calls wq_sleep with the address of `struct\n   ext_wait_queue` on function stack (aliased as `ewq_addr` here) - it\n   holds a valid `struct ext_wait_queue *` as long as the stack has not\n   been overwritten.\n\n2. `ewq_addr` gets added to info-\u003ee_wait_q[RECV].list in wq_add, and\n   do_mq_timedsend receives it via wq_get_first_waiter(info, RECV) to call\n   __pipelined_op.\n\n3. Sender calls __pipelined_op::smp_store_release(\u0026this-\u003estate,\n   STATE_READY).  Here is where the race window begins.  (`this` is\n   `ewq_addr`.)\n\n4. If the receiver wakes up now in do_mq_timedreceive::wq_sleep, it\n   will see `state == STATE_READY` and break.\n\n5. do_mq_timedreceive returns, and `ewq_addr` is no longer guaranteed\n   to be a `struct ext_wait_queue *` since it was on do_mq_timedreceive\u0027s\n   stack.  (Although the address may not get overwritten until another\n   function happens to touch it, which means it can persist around for an\n   indefinite time.)\n\n6. do_mq_timedsend::__pipelined_op() still believes `ewq_addr` is a\n   `struct ext_wait_queue *`, and uses it to find a task_struct to pass to\n   the wake_q_add_safe call.  In the lucky case where nothing has\n   overwritten `ewq_addr` yet, `ewq_addr-\u003etask` is the right task_struct.\n   In the unlucky case, __pipelined_op::wake_q_add_safe gets handed a\n   bogus address as the receiver\u0027s task_struct causing the crash.\n\ndo_mq_timedsend::__pipelined_op() should not dereference `this` after\nsetting STATE_READY, as the receiver counterpart is now free to return.\nChange __pipelined_op to call wake_q_add_safe on the receiver\u0027s\ntask_struct returned by get_task_struct, instead of dereferencing `this`\nwhich sits on the receiver\u0027s stack.\n\nAs Manfred pointed out, the race potentially also exists in\nipc/msg.c::expunge_all and ipc/sem.c::wake_up_sem_queue_prepare.  Fix\nthose in the same way."
    },
    {
      "lang": "es",
      "value": "En el kernel de Linux, se resolvi\u00f3 la siguiente vulnerabilidad: ipc/mqueue, msg, sem: evite confiar en una referencia de pila despu\u00e9s de su vencimiento do_mq_timedreceive llama a wq_sleep con una direcci\u00f3n local de pila. El remitente (do_mq_timedsend) usa esta direcci\u00f3n para luego llamar a pipelined_send. Esto conduce a una ejecuci\u00f3n muy dif\u00edcil de desencadenar en la que una llamada do_mq_timedreceive puede regresar y dejar que do_mq_timedsend dependa de una direcci\u00f3n no v\u00e1lida, lo que provoca el siguiente bloqueo: RIP: 0010:wake_q_add_safe+0x13/0x60 Seguimiento de llamadas: __x64_sys_mq_timedsend+0x2a9/0x490 do_syscall_64+0x80 /0x680 Entry_SYSCALL_64_after_hwframe+0x44/0xa9 RIP: 0033:0x7f5928e40343 La ejecuci\u00f3n ocurre como: 1. do_mq_timedreceive llama a wq_sleep con la direcci\u00f3n de `struct ext_wait_queue` en la pila de funciones (alias `ewq_addr` aqu\u00ed): contiene una `struct ext_wait_queue * v\u00e1lida ` siempre y cuando la pila no haya sido sobrescrita. 2. `ewq_addr` se agrega a info-\u0026gt;e_wait_q[RECV].list en wq_add, y do_mq_timedsend lo recibe a trav\u00e9s de wq_get_first_waiter(info, RECV) para llamar a __pipelined_op. 3. El remitente llama a __pipelined_op::smp_store_release(\u0026amp;this-\u0026gt;state, STATE_READY). Aqu\u00ed es donde comienza la ventana de ejecuci\u00f3n. (`esto` es `ewq_addr`.) 4. Si el receptor se activa ahora en do_mq_timedreceive::wq_sleep, ver\u00e1 `state == STATE_READY` y se interrumpir\u00e1. 5. do_mq_timedreceive regresa y ya no se garantiza que `ewq_addr` sea una `struct ext_wait_queue *` ya que estaba en la pila de do_mq_timedreceive. (Aunque es posible que la direcci\u00f3n no se sobrescriba hasta que otra funci\u00f3n la toque, lo que significa que puede persistir por un tiempo indefinido). 6. do_mq_timedsend::__pipelined_op() todav\u00eda cree que `ewq_addr` es una `struct ext_wait_queue *`, y lo usa para encontrar una task_struct para pasar a la llamada wake_q_add_safe. En el afortunado caso de que nada haya sobrescrito `ewq_addr` todav\u00eda, `ewq_addr-\u0026gt;task` es la estructura de tarea correcta. En el desafortunado caso, __pipelined_op::wake_q_add_safe recibe una direcci\u00f3n falsa como la task_struct del receptor que causa el bloqueo. do_mq_timedsend::__pipelined_op() no debe eliminar la referencia a \"esto\" despu\u00e9s de configurar STATE_READY, ya que la contraparte del receptor ahora puede regresar. Cambie __pipelined_op para llamar a wake_q_add_safe en el task_struct del receptor devuelto por get_task_struct, en lugar de desreferenciar \"this\" que se encuentra en la pila del receptor. Como se\u00f1al\u00f3 Manfred, la ejecuci\u00f3n tambi\u00e9n existe potencialmente en ipc/msg.c::expunge_all e ipc/sem.c::wake_up_sem_queue_prepare. Arr\u00e9glelos de la misma manera."
    }
  ],
  "id": "CVE-2021-47069",
  "lastModified": "2026-08-04T10:16:44.070",
  "metrics": {
    "cvssMetricV31": [
      {
        "cvssData": {
          "attackComplexity": "LOW",
          "attackVector": "LOCAL",
          "availabilityImpact": "HIGH",
          "baseScore": 7.8,
          "baseSeverity": "HIGH",
          "confidentialityImpact": "HIGH",
          "integrityImpact": "HIGH",
          "privilegesRequired": "LOW",
          "scope": "UNCHANGED",
          "userInteraction": "NONE",
          "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
          "version": "3.1"
        },
        "exploitabilityScore": 1.8,
        "impactScore": 5.9,
        "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "type": "Secondary"
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          "baseScore": 7.0,
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        "impactScore": 5.9,
        "source": "nvd@nist.gov",
        "type": "Primary"
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        "ssvcData": {
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          "options": [
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            {
              "automatable": "no"
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          "role": "CISA Coordinator",
          "timestamp": "2024-06-21T16:15:09.996738Z",
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  "published": "2024-03-01T22:15:46.857",
  "references": [
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      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
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      "url": "https://git.kernel.org/stable/c/a11ddb37bf367e6b5239b95ca759e5389bb46048"
    }
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  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "vulnStatus": "Modified",
  "weaknesses": [
    {
      "description": [
        {
          "lang": "en",
          "value": "CWE-672"
        }
      ],
      "source": "nvd@nist.gov",
      "type": "Primary"
    }
  ]
}

CVE-2021-47069 (GCVE-0-2021-47069)

Vulnerability from cvelistv5 – Published: 2024-03-01 21:15 – Updated: 2026-08-05 08:45

Title

ipc/mqueue, msg, sem: avoid relying on a stack reference past its expiry

Summary

Severity

7.8 (High)


                        
                          CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

SSVC

Exploitation: none Automatable: no Technical Impact: partial

CISA Coordinator · CISA-ADP (v2.0.3)

Decision recorded 2024-06-21 16:15 UTC

Assigner

Linux CNA under the mitre root

CNA scorecard D 53/100 over 6856 records in the last 180 days details

References

3 references

URL	Tags
https://git.kernel.org/stable/c/4528c0c323085e645…
https://git.kernel.org/stable/c/807fa14536b26803b…
https://git.kernel.org/stable/c/a11ddb37bf367e6b5…

Impacted products

2 products

Vendor	Product	Version
Linux	Linux	Affected: c5b2cbdbdac563f46ecd5e187253ab1abbd6fc04 , < 4528c0c323085e645b8765913b4a7fd42cf49b65 (git) Affected: c5b2cbdbdac563f46ecd5e187253ab1abbd6fc04 , < 807fa14536b26803b858da878b643be72952a097 (git) Affected: c5b2cbdbdac563f46ecd5e187253ab1abbd6fc04 , < a11ddb37bf367e6b5239b95ca759e5389bb46048 (git)
Linux	Linux	Affected: 5.6 Unaffected: 0 , < 5.6 (semver) Unaffected: 5.10.40 , ≤ 5.10.* (semver) Unaffected: 5.12.7 , ≤ 5.12.* (semver) Unaffected: 5.13 , ≤ * (original_commit_for_fix)

Show details on NVD website

JSON

To clipboard

{
  "containers": {
    "adp": [
      {
        "metrics": [
          {
            "other": {
              "content": {
                "id": "CVE-2021-47069",
                "options": [
                  {
                    "Exploitation": "none"
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                  },
                  {
                    "Technical Impact": "partial"
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                ],
                "role": "CISA Coordinator",
                "timestamp": "2024-06-21T16:15:09.996738Z",
                "version": "2.0.3"
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          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
        },
        "title": "CISA ADP Vulnrichment"
      },
      {
        "providerMetadata": {
          "dateUpdated": "2024-08-04T05:24:39.653Z",
          "orgId": "af854a3a-2127-422b-91ae-364da2661108",
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            "url": "https://git.kernel.org/stable/c/a11ddb37bf367e6b5239b95ca759e5389bb46048"
          }
        ],
        "title": "CVE Program Container"
      }
    ],
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "ipc/mqueue.c",
            "ipc/msg.c",
            "ipc/sem.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "4528c0c323085e645b8765913b4a7fd42cf49b65",
              "status": "affected",
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              "versionType": "git"
            },
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        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
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            "ipc/msg.c",
            "ipc/sem.c"
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          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
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              "version": "5.6"
            },
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              "lessThan": "5.6",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
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            {
              "lessThanOrEqual": "5.12.*",
              "status": "unaffected",
              "version": "5.12.7",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "5.13",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "5.10.40",
                  "versionStartIncluding": "5.6",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "5.12.7",
                  "versionStartIncluding": "5.6",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "5.13",
                  "versionStartIncluding": "5.6",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nipc/mqueue, msg, sem: avoid relying on a stack reference past its expiry\n\ndo_mq_timedreceive calls wq_sleep with a stack local address.  The\nsender (do_mq_timedsend) uses this address to later call pipelined_send.\n\nThis leads to a very hard to trigger race where a do_mq_timedreceive\ncall might return and leave do_mq_timedsend to rely on an invalid\naddress, causing the following crash:\n\n  RIP: 0010:wake_q_add_safe+0x13/0x60\n  Call Trace:\n   __x64_sys_mq_timedsend+0x2a9/0x490\n   do_syscall_64+0x80/0x680\n   entry_SYSCALL_64_after_hwframe+0x44/0xa9\n  RIP: 0033:0x7f5928e40343\n\nThe race occurs as:\n\n1. do_mq_timedreceive calls wq_sleep with the address of `struct\n   ext_wait_queue` on function stack (aliased as `ewq_addr` here) - it\n   holds a valid `struct ext_wait_queue *` as long as the stack has not\n   been overwritten.\n\n2. `ewq_addr` gets added to info-\u003ee_wait_q[RECV].list in wq_add, and\n   do_mq_timedsend receives it via wq_get_first_waiter(info, RECV) to call\n   __pipelined_op.\n\n3. Sender calls __pipelined_op::smp_store_release(\u0026this-\u003estate,\n   STATE_READY).  Here is where the race window begins.  (`this` is\n   `ewq_addr`.)\n\n4. If the receiver wakes up now in do_mq_timedreceive::wq_sleep, it\n   will see `state == STATE_READY` and break.\n\n5. do_mq_timedreceive returns, and `ewq_addr` is no longer guaranteed\n   to be a `struct ext_wait_queue *` since it was on do_mq_timedreceive\u0027s\n   stack.  (Although the address may not get overwritten until another\n   function happens to touch it, which means it can persist around for an\n   indefinite time.)\n\n6. do_mq_timedsend::__pipelined_op() still believes `ewq_addr` is a\n   `struct ext_wait_queue *`, and uses it to find a task_struct to pass to\n   the wake_q_add_safe call.  In the lucky case where nothing has\n   overwritten `ewq_addr` yet, `ewq_addr-\u003etask` is the right task_struct.\n   In the unlucky case, __pipelined_op::wake_q_add_safe gets handed a\n   bogus address as the receiver\u0027s task_struct causing the crash.\n\ndo_mq_timedsend::__pipelined_op() should not dereference `this` after\nsetting STATE_READY, as the receiver counterpart is now free to return.\nChange __pipelined_op to call wake_q_add_safe on the receiver\u0027s\ntask_struct returned by get_task_struct, instead of dereferencing `this`\nwhich sits on the receiver\u0027s stack.\n\nAs Manfred pointed out, the race potentially also exists in\nipc/msg.c::expunge_all and ipc/sem.c::wake_up_sem_queue_prepare.  Fix\nthose in the same way."
        }
      ],
      "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 - The bug is triggered through local IPC syscalls (mq_timedsend/mq_timedreceive, msgsnd/msgrcv/msgctl, semop/semctl) and is not reachable by processing remote or adjacent-link network traffic.\nAC:L - The attacker fully controls both sides of the race by running concurrent sender and receiver (or RMID) operations on their own message queue or semaphore set, so success does not depend on an external condition outside their influence.\nPR:L - An unprivileged local user can mq_open/msgget/semget their own objects and exercise send/receive/RMID paths; CAP_SYS_RESOURCE is only needed to exceed resource limits, not to hit the vulnerable code.\nUI:N - The attacker performs the concurrent IPC operations themselves and does not need any separate victim or administrator action.\nS:U - This is a standard in-kernel stack use-after-free within the host OS authority and does not cross a VM, IOMMU, or other security boundary.\nC:H - The dangling stack pointer is reloaded into wake_q_add_safe as a task_struct *, and this stack UAF can be leveraged via stack reuse/heap primitives for arbitrary kernel memory disclosure under UAF scoring guidance.\nI:H - wake_q_add_safe/__wake_q_add perform cmpxchg and list writes through the attacker-influenced task pointer and may put_task_struct/wake_up_process on a bogus object, yielding write and control-flow hijack primitives.\nA:H - The issue was observed to crash in wake_q_add_safe with a bogus task_struct pointer, so kernel oops/panic availability impact is High even without a full exploit."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-08-05T08:45:50.647Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/4528c0c323085e645b8765913b4a7fd42cf49b65"
        },
        {
          "url": "https://git.kernel.org/stable/c/807fa14536b26803b858da878b643be72952a097"
        },
        {
          "url": "https://git.kernel.org/stable/c/a11ddb37bf367e6b5239b95ca759e5389bb46048"
        }
      ],
      "title": "ipc/mqueue, msg, sem: avoid relying on a stack reference past its expiry",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2021-47069",
    "datePublished": "2024-03-01T21:15:08.598Z",
    "dateReserved": "2024-02-29T22:33:44.296Z",
    "dateUpdated": "2026-08-05T08:45:50.647Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}

Sightings

Author	Source	Type	Date	Other

Nomenclature

Seen: The vulnerability was mentioned, discussed, or observed by the user.
Confirmed: The vulnerability has been validated from an analyst's perspective.
Published Proof of Concept: A public proof of concept is available for this vulnerability.
Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
Not confirmed: The user expressed doubt about the validity of the vulnerability.
Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.

Vulnerability timeline

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The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base model, served locally by ML-Gateway. They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
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Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.

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