Vulnerability-Lookup

FKIE_CVE-2021-47163

Vulnerability from fkie_nvd - Published: 2024-03-25 10:15 - 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
5.5 (Medium) - CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Summary

In the Linux kernel, the following vulnerability has been resolved: tipc: wait and exit until all work queues are done On some host, a crash could be triggered simply by repeating these commands several times: # modprobe tipc # tipc bearer enable media udp name UDP1 localip 127.0.0.1 # rmmod tipc [] BUG: unable to handle kernel paging request at ffffffffc096bb00 [] Workqueue: events 0xffffffffc096bb00 [] Call Trace: [] ? process_one_work+0x1a7/0x360 [] ? worker_thread+0x30/0x390 [] ? create_worker+0x1a0/0x1a0 [] ? kthread+0x116/0x130 [] ? kthread_flush_work_fn+0x10/0x10 [] ? ret_from_fork+0x35/0x40 When removing the TIPC module, the UDP tunnel sock will be delayed to release in a work queue as sock_release() can't be done in rtnl_lock(). If the work queue is schedule to run after the TIPC module is removed, kernel will crash as the work queue function cleanup_beareri() code no longer exists when trying to invoke it. To fix it, this patch introduce a member wq_count in tipc_net to track the numbers of work queues in schedule, and wait and exit until all work queues are done in tipc_exit_net().

References

URL	Tags
416baaa9-dc9f-4396-8d5f-8c081fb06d67	https://git.kernel.org/stable/c/04c26faa51d1e2fe71cf13c45791f5174c37f986	Patch
416baaa9-dc9f-4396-8d5f-8c081fb06d67	https://git.kernel.org/stable/c/5195ec5e365a2a9331bfeb585b613a6e94f98dba	Patch
416baaa9-dc9f-4396-8d5f-8c081fb06d67	https://git.kernel.org/stable/c/b9f5b7ad4ac3af006443f535b1ce7bff1d130d7d	Patch
416baaa9-dc9f-4396-8d5f-8c081fb06d67	https://git.kernel.org/stable/c/d1f76dfadaf8f47ed1753f97dbcbd41c16215ffa	Patch
af854a3a-2127-422b-91ae-364da2661108	https://git.kernel.org/stable/c/04c26faa51d1e2fe71cf13c45791f5174c37f986	Patch
af854a3a-2127-422b-91ae-364da2661108	https://git.kernel.org/stable/c/5195ec5e365a2a9331bfeb585b613a6e94f98dba	Patch
af854a3a-2127-422b-91ae-364da2661108	https://git.kernel.org/stable/c/b9f5b7ad4ac3af006443f535b1ce7bff1d130d7d	Patch
af854a3a-2127-422b-91ae-364da2661108	https://git.kernel.org/stable/c/d1f76dfadaf8f47ed1753f97dbcbd41c16215ffa	Patch

Impacted products

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

JSON

To clipboard

{
  "affected": [
    {
      "affectedData": [
        {
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            "net/tipc/core.c",
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  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\ntipc: wait and exit until all work queues are done\n\nOn some host, a crash could be triggered simply by repeating these\ncommands several times:\n\n  # modprobe tipc\n  # tipc bearer enable media udp name UDP1 localip 127.0.0.1\n  # rmmod tipc\n\n  [] BUG: unable to handle kernel paging request at ffffffffc096bb00\n  [] Workqueue: events 0xffffffffc096bb00\n  [] Call Trace:\n  []  ? process_one_work+0x1a7/0x360\n  []  ? worker_thread+0x30/0x390\n  []  ? create_worker+0x1a0/0x1a0\n  []  ? kthread+0x116/0x130\n  []  ? kthread_flush_work_fn+0x10/0x10\n  []  ? ret_from_fork+0x35/0x40\n\nWhen removing the TIPC module, the UDP tunnel sock will be delayed to\nrelease in a work queue as sock_release() can\u0027t be done in rtnl_lock().\nIf the work queue is schedule to run after the TIPC module is removed,\nkernel will crash as the work queue function cleanup_beareri() code no\nlonger exists when trying to invoke it.\n\nTo fix it, this patch introduce a member wq_count in tipc_net to track\nthe numbers of work queues in schedule, and  wait and exit until all\nwork queues are done in tipc_exit_net()."
    },
    {
      "lang": "es",
      "value": "En el kernel de Linux, se ha resuelto la siguiente vulnerabilidad: tipc: espere y salga hasta que todas las colas de trabajo est\u00e9n terminadas. En algunos hosts, se podr\u00eda desencadenar un bloqueo simplemente repitiendo estos comandos varias veces: # modprobe tipc # tipc portador habilitar media udp nombre UDP1 localip 127.0.0.1 # rmmod tipc [] ERROR: no se puede manejar la solicitud de paginaci\u00f3n del kernel en ffffffffc096bb00 [] Cola de trabajo: eventos 0xffffffffc096bb00 [] Seguimiento de llamadas: []? proceso_one_work+0x1a7/0x360 []? hilo_trabajador+0x30/0x390 []? crear_trabajador+0x1a0/0x1a0 []? kthread+0x116/0x130 []? kthread_flush_work_fn+0x10/0x10 []? ret_from_fork+0x35/0x40 Al retirar el m\u00f3dulo TIPC, el calcet\u00edn del t\u00fanel UDP se retrasar\u00e1 para liberarse en una cola de trabajo, ya que sock_release() no se puede realizar en rtnl_lock(). Si la cola de trabajo est\u00e1 programada para ejecutarse despu\u00e9s de eliminar el m\u00f3dulo TIPC, el kernel fallar\u00e1 porque el c\u00f3digo de la funci\u00f3n de cola de trabajo cleanup_beareri() ya no existe al intentar invocarlo. Para solucionarlo, este parche introduce un miembro wq_count en tipc_net para rastrear el n\u00famero de colas de trabajo programadas y esperar y salir hasta que todas las colas de trabajo est\u00e9n terminadas en tipc_exit_net()."
    }
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  "id": "CVE-2021-47163",
  "lastModified": "2026-08-04T10:16:49.993",
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}

CVE-2021-47163 (GCVE-0-2021-47163)

Vulnerability from cvelistv5 – Published: 2024-03-25 09:16 – Updated: 2026-08-05 08:46

Title

tipc: wait and exit until all work queues are done

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 2024-04-01 19:41 UTC

Assigner

Linux mitre root

References

4 references

URL	Tags
https://git.kernel.org/stable/c/d1f76dfadaf8f47ed…
https://git.kernel.org/stable/c/5195ec5e365a2a933…
https://git.kernel.org/stable/c/b9f5b7ad4ac3af006…
https://git.kernel.org/stable/c/04c26faa51d1e2fe7…

Impacted products

2 products

Vendor	Product	Version
Linux	Linux	Affected: d0f91938bede204a343473792529e0db7d599836 , < d1f76dfadaf8f47ed1753f97dbcbd41c16215ffa (git) Affected: d0f91938bede204a343473792529e0db7d599836 , < 5195ec5e365a2a9331bfeb585b613a6e94f98dba (git) Affected: d0f91938bede204a343473792529e0db7d599836 , < b9f5b7ad4ac3af006443f535b1ce7bff1d130d7d (git) Affected: d0f91938bede204a343473792529e0db7d599836 , < 04c26faa51d1e2fe71cf13c45791f5174c37f986 (git)
Linux	Linux	Affected: 4.1 Unaffected: 0 , < 4.1 (semver) Unaffected: 5.4.124 , ≤ 5.4.* (semver) Unaffected: 5.10.42 , ≤ 5.10.* (semver) Unaffected: 5.12.9 , ≤ 5.12.* (semver) Unaffected: 5.13 , ≤ * (original_commit_for_fix)

Show details on NVD website

JSON

To clipboard

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                  "versionEndExcluding": "5.13",
                  "versionStartIncluding": "4.1",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\ntipc: wait and exit until all work queues are done\n\nOn some host, a crash could be triggered simply by repeating these\ncommands several times:\n\n  # modprobe tipc\n  # tipc bearer enable media udp name UDP1 localip 127.0.0.1\n  # rmmod tipc\n\n  [] BUG: unable to handle kernel paging request at ffffffffc096bb00\n  [] Workqueue: events 0xffffffffc096bb00\n  [] Call Trace:\n  []  ? process_one_work+0x1a7/0x360\n  []  ? worker_thread+0x30/0x390\n  []  ? create_worker+0x1a0/0x1a0\n  []  ? kthread+0x116/0x130\n  []  ? kthread_flush_work_fn+0x10/0x10\n  []  ? ret_from_fork+0x35/0x40\n\nWhen removing the TIPC module, the UDP tunnel sock will be delayed to\nrelease in a work queue as sock_release() can\u0027t be done in rtnl_lock().\nIf the work queue is schedule to run after the TIPC module is removed,\nkernel will crash as the work queue function cleanup_beareri() code no\nlonger exists when trying to invoke it.\n\nTo fix it, this patch introduce a member wq_count in tipc_net to track\nthe numbers of work queues in schedule, and  wait and exit until all\nwork queues are done in tipc_exit_net()."
        }
      ],
      "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 reached via local tipc generic-netlink bearer enable/disable and netns teardown (or local rmmod of tipc); it is not triggered by processing unsolicited remote TIPC/UDP packets.\nAC:L - The attacker controls both sides of the race by enabling a UDP bearer and then destroying the netns (or repeating modprobe/enable/rmmod), so the pending cleanup_bearer work is reliably left running after tipc_exit_net returns.\nPR:L - At the time of this bug, TIPCv2 bearer mutators lacked GENL_ADMIN_PERM, and an unprivileged user can create a user+net namespace (unshare -Urn) and enable a tipc UDP bearer whenever tipc is loaded; CAP_NET_ADMIN in a userns is also Low per guidance.\nUI:N - No victim action is required; the attacker enables the bearer and tears down their own netns (or unloads tipc) entirely on their own.\nS:U - Impact is a host-kernel use-after-free/crash within the same kernel security authority; there is no VM, IOMMU, or sandbox boundary crossing.\nC:H - tipc_exit_net returns without waiting for cleanup_bearer while kernel UDP sockets hold no netns refcount, so the work runs against freed net/module state; this UAF can be leveraged for arbitrary kernel memory disclosure.\nI:H - The same UAF (and the module-unload path that invokes freed cleanup_bearer text via the workqueue) is memory corruption exploitable for write primitives and control-flow hijacking, not merely a clean crash.\nA:H - The reported failure is a kernel paging-request oops when the workqueue runs after tipc teardown/unload, and the netns UAF path likewise causes kernel crashes."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-08-05T08:46:27.215Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/d1f76dfadaf8f47ed1753f97dbcbd41c16215ffa"
        },
        {
          "url": "https://git.kernel.org/stable/c/5195ec5e365a2a9331bfeb585b613a6e94f98dba"
        },
        {
          "url": "https://git.kernel.org/stable/c/b9f5b7ad4ac3af006443f535b1ce7bff1d130d7d"
        },
        {
          "url": "https://git.kernel.org/stable/c/04c26faa51d1e2fe71cf13c45791f5174c37f986"
        }
      ],
      "title": "tipc: wait and exit until all work queues are done",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2021-47163",
    "datePublished": "2024-03-25T09:16:16.676Z",
    "dateReserved": "2024-03-25T09:12:14.109Z",
    "dateUpdated": "2026-08-05T08:46:27.215Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}

Sightings

Author	Source	Type	Date	Other

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Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.

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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FKIE_CVE-2021-47163

CVE-2021-47163 (GCVE-0-2021-47163)

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