Vulnerability-Lookup

GHSA-6W2X-9PHQ-JCJC

Vulnerability from github – Published: 2026-10-18 18:31 – Updated: 2026-10-18 18:31

Details

In the Linux kernel, the following vulnerability has been resolved:

workqueue: Fix NULL current_pwq deref in flush dependency check

check_flush_dependency() uses current_wq_worker() to determine whether the caller is a workqueue worker and then dereferences worker->current_pwq to test whether the current workqueue is WQ_MEM_RECLAIM.

current_wq_worker() only means that %current has PF_WQ_WORKER set. A kworker can reach check_flush_dependency() while it is not executing a work item. One such path is worker_thread() acting as the pool manager, where create_worker() does GFP_KERNEL allocation and the allocation path invokes the OOM notifier. In that state worker->current_pwq is NULL because current_pwq is set only by process_one_work() and cleared again after the work function returns.

[ 416.760634][ T375] Call trace: [ 416.760638][ T375] check_flush_dependency+0x80/0x120 (P) [ 416.760648][ T375] __flush_work+0x98/0x224 [ 416.760657][ T375] flush_work+0x30/0x44 [ 416.760665][ T375] ... [ 416.760710][ T375] blocking_notifier_call_chain+0x58/0xa0 [ 416.760719][ T375] out_of_memory+0xb4/0x458 [ 416.760730][ T375] __alloc_pages_may_oom+0x11c/0x1a8 [ 416.760739][ T375] __alloc_pages_slowpath+0x314/0x46c [ 416.760746][ T375] __alloc_frozen_pages_noprof+0x110/0x1a4 [ 416.760753][ T375] new_slab+0x12c/0x484 [ 416.760759][ T375] ___slab_alloc+0x7a8/0xc7c [ 416.760765][ T375] __slab_alloc+0x74/0xd8 [ 416.760772][ T375] __kmalloc_cache_node_noprof+0x2ac/0x304 [ 416.760779][ T375] alloc_worker+0x28/0x60 [ 416.760785][ T375] create_worker+0x4c/0x20c [ 416.760790][ T375] worker_thread+0xe8/0x2b8 [ 416.760796][ T375] kthread+0x1a8/0x200 [ 416.760805][ T375] ret_from_fork+0x10/0x20

Guard the WQ_MEM_RECLAIM-worker warning with worker->current_pwq. If the kworker is not currently executing a work item, there is no current workqueue to diagnose with that warning. The PF_MEMALLOC warning is left unchanged so explicit reclaim context flushing a !WQ_MEM_RECLAIM target is still reported.

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{
  "affected": [],
  "aliases": [
    "CVE-2026-98537"
  ],
  "database_specific": {
    "cwe_ids": [],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-10-18T16:17:05Z",
    "severity": null
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nworkqueue: Fix NULL current_pwq deref in flush dependency check\n\ncheck_flush_dependency() uses current_wq_worker() to determine whether\nthe caller is a workqueue worker and then dereferences worker-\u003ecurrent_pwq\nto test whether the current workqueue is WQ_MEM_RECLAIM.\n\ncurrent_wq_worker() only means that %current has PF_WQ_WORKER set. A\nkworker can reach check_flush_dependency() while it is not executing a\nwork item. One such path is worker_thread() acting as the pool manager,\nwhere create_worker() does GFP_KERNEL allocation and the allocation path\ninvokes the OOM notifier. In that state worker-\u003ecurrent_pwq is NULL\nbecause current_pwq is set only by process_one_work() and cleared again\nafter the work function returns.\n\n[  416.760634][  T375] Call trace:\n[  416.760638][  T375]  check_flush_dependency+0x80/0x120 (P)\n[  416.760648][  T375]  __flush_work+0x98/0x224\n[  416.760657][  T375]  flush_work+0x30/0x44\n[  416.760665][  T375]  ...\n[  416.760710][  T375]  blocking_notifier_call_chain+0x58/0xa0\n[  416.760719][  T375]  out_of_memory+0xb4/0x458\n[  416.760730][  T375]  __alloc_pages_may_oom+0x11c/0x1a8\n[  416.760739][  T375]  __alloc_pages_slowpath+0x314/0x46c\n[  416.760746][  T375]  __alloc_frozen_pages_noprof+0x110/0x1a4\n[  416.760753][  T375]  new_slab+0x12c/0x484\n[  416.760759][  T375]  ___slab_alloc+0x7a8/0xc7c\n[  416.760765][  T375]  __slab_alloc+0x74/0xd8\n[  416.760772][  T375]  __kmalloc_cache_node_noprof+0x2ac/0x304\n[  416.760779][  T375]  alloc_worker+0x28/0x60\n[  416.760785][  T375]  create_worker+0x4c/0x20c\n[  416.760790][  T375]  worker_thread+0xe8/0x2b8\n[  416.760796][  T375]  kthread+0x1a8/0x200\n[  416.760805][  T375]  ret_from_fork+0x10/0x20\n\nGuard the WQ_MEM_RECLAIM-worker warning with worker-\u003ecurrent_pwq. If the\nkworker is not currently executing a work item, there is no current\nworkqueue to diagnose with that warning. The PF_MEMALLOC warning is left\nunchanged so explicit reclaim context flushing a !WQ_MEM_RECLAIM target\nis still reported.",
  "id": "GHSA-6w2x-9phq-jcjc",
  "modified": "2026-10-18T18:31:53Z",
  "published": "2026-10-18T18:31:53Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-98537"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/0c6b9b1e295aeff1132ac7aa738148cc65f06485"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/1dccf5dc2f8fe688270b261ca4216e03c6a1e674"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/513121e69388604619ea8c0ee07e86a3d1b5b5dc"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/8ffececcb88262389b4f91fed0fe4884b68204bc"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/9bb739a5c5a570c28a62afb98e9326e2a49743c1"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/cc190a6a1d20b87e6a9435202fc2a3bd84c79fb3"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/db6365ced4d5855e321f772b240c0e473bcfcdd5"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/f97e6d0572d1b39998e053732332bc3cfdd0b9aa"
    }
  ],
  "schema_version": "1.4.0",
  "severity": []
}

CVE-2026-98537 (GCVE-0-2026-98537)

Vulnerability from cvelistv5 – Published: 2026-10-18 15:18 – Updated: 2026-10-19 09:21

Title

workqueue: Fix NULL current_pwq deref in flush dependency check

Summary

In the Linux kernel, the following vulnerability has been resolved: workqueue: Fix NULL current_pwq deref in flush dependency check check_flush_dependency() uses current_wq_worker() to determine whether the caller is a workqueue worker and then dereferences worker->current_pwq to test whether the current workqueue is WQ_MEM_RECLAIM. current_wq_worker() only means that %current has PF_WQ_WORKER set. A kworker can reach check_flush_dependency() while it is not executing a work item. One such path is worker_thread() acting as the pool manager, where create_worker() does GFP_KERNEL allocation and the allocation path invokes the OOM notifier. In that state worker->current_pwq is NULL because current_pwq is set only by process_one_work() and cleared again after the work function returns. [ 416.760634][ T375] Call trace: [ 416.760638][ T375] check_flush_dependency+0x80/0x120 (P) [ 416.760648][ T375] __flush_work+0x98/0x224 [ 416.760657][ T375] flush_work+0x30/0x44 [ 416.760665][ T375] ... [ 416.760710][ T375] blocking_notifier_call_chain+0x58/0xa0 [ 416.760719][ T375] out_of_memory+0xb4/0x458 [ 416.760730][ T375] __alloc_pages_may_oom+0x11c/0x1a8 [ 416.760739][ T375] __alloc_pages_slowpath+0x314/0x46c [ 416.760746][ T375] __alloc_frozen_pages_noprof+0x110/0x1a4 [ 416.760753][ T375] new_slab+0x12c/0x484 [ 416.760759][ T375] ___slab_alloc+0x7a8/0xc7c [ 416.760765][ T375] __slab_alloc+0x74/0xd8 [ 416.760772][ T375] __kmalloc_cache_node_noprof+0x2ac/0x304 [ 416.760779][ T375] alloc_worker+0x28/0x60 [ 416.760785][ T375] create_worker+0x4c/0x20c [ 416.760790][ T375] worker_thread+0xe8/0x2b8 [ 416.760796][ T375] kthread+0x1a8/0x200 [ 416.760805][ T375] ret_from_fork+0x10/0x20 Guard the WQ_MEM_RECLAIM-worker warning with worker->current_pwq. If the kworker is not currently executing a work item, there is no current workqueue to diagnose with that warning. The PF_MEMALLOC warning is left unchanged so explicit reclaim context flushing a !WQ_MEM_RECLAIM target is still reported.

Severity

No CVSS data available.

Assigner

Linux CNA under the mitre root

CNA scorecard D 53/100 over 6820 records in the last 180 days details

References

8 references

URL	Tags
https://git.kernel.org/stable/c/8ffececcb88262389…
https://git.kernel.org/stable/c/9bb739a5c5a570c28…
https://git.kernel.org/stable/c/cc190a6a1d20b87e6…
https://git.kernel.org/stable/c/513121e6938860461…
https://git.kernel.org/stable/c/0c6b9b1e295aeff11…
https://git.kernel.org/stable/c/1dccf5dc2f8fe6882…
https://git.kernel.org/stable/c/f97e6d0572d1b3999…
https://git.kernel.org/stable/c/db6365ced4d5855e3…

Impacted products

2 products

Vendor	Product	Version
Linux	Linux	Affected: fca839c00a12d682cb59b3b620d109a1d850b262 , < 8ffececcb88262389b4f91fed0fe4884b68204bc (git) Affected: fca839c00a12d682cb59b3b620d109a1d850b262 , < 9bb739a5c5a570c28a62afb98e9326e2a49743c1 (git) Affected: fca839c00a12d682cb59b3b620d109a1d850b262 , < cc190a6a1d20b87e6a9435202fc2a3bd84c79fb3 (git) Affected: fca839c00a12d682cb59b3b620d109a1d850b262 , < 513121e69388604619ea8c0ee07e86a3d1b5b5dc (git) Affected: fca839c00a12d682cb59b3b620d109a1d850b262 , < 0c6b9b1e295aeff1132ac7aa738148cc65f06485 (git) Affected: fca839c00a12d682cb59b3b620d109a1d850b262 , < 1dccf5dc2f8fe688270b261ca4216e03c6a1e674 (git) Affected: fca839c00a12d682cb59b3b620d109a1d850b262 , < f97e6d0572d1b39998e053732332bc3cfdd0b9aa (git) Affected: fca839c00a12d682cb59b3b620d109a1d850b262 , < db6365ced4d5855e321f772b240c0e473bcfcdd5 (git)
Linux	Linux	Affected: 4.5 Unaffected: 0 , < 4.5 (semver) Unaffected: 5.10.271 , ≤ 5.10.* (semver) Unaffected: 5.15.222 , ≤ 5.15.* (semver) Unaffected: 6.1.189 , ≤ 6.1.* (semver) Unaffected: 6.6.158 , ≤ 6.6.* (semver) Unaffected: 6.12.112 , ≤ 6.12.* (semver) Unaffected: 6.18.55 , ≤ 6.18.* (semver) Unaffected: 7.2.9 , ≤ 7.2.* (semver) Unaffected: 7.3 , ≤ * (original_commit_for_fix)

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{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "kernel/workqueue.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "8ffececcb88262389b4f91fed0fe4884b68204bc",
              "status": "affected",
              "version": "fca839c00a12d682cb59b3b620d109a1d850b262",
              "versionType": "git"
            },
            {
              "lessThan": "9bb739a5c5a570c28a62afb98e9326e2a49743c1",
              "status": "affected",
              "version": "fca839c00a12d682cb59b3b620d109a1d850b262",
              "versionType": "git"
            },
            {
              "lessThan": "cc190a6a1d20b87e6a9435202fc2a3bd84c79fb3",
              "status": "affected",
              "version": "fca839c00a12d682cb59b3b620d109a1d850b262",
              "versionType": "git"
            },
            {
              "lessThan": "513121e69388604619ea8c0ee07e86a3d1b5b5dc",
              "status": "affected",
              "version": "fca839c00a12d682cb59b3b620d109a1d850b262",
              "versionType": "git"
            },
            {
              "lessThan": "0c6b9b1e295aeff1132ac7aa738148cc65f06485",
              "status": "affected",
              "version": "fca839c00a12d682cb59b3b620d109a1d850b262",
              "versionType": "git"
            },
            {
              "lessThan": "1dccf5dc2f8fe688270b261ca4216e03c6a1e674",
              "status": "affected",
              "version": "fca839c00a12d682cb59b3b620d109a1d850b262",
              "versionType": "git"
            },
            {
              "lessThan": "f97e6d0572d1b39998e053732332bc3cfdd0b9aa",
              "status": "affected",
              "version": "fca839c00a12d682cb59b3b620d109a1d850b262",
              "versionType": "git"
            },
            {
              "lessThan": "db6365ced4d5855e321f772b240c0e473bcfcdd5",
              "status": "affected",
              "version": "fca839c00a12d682cb59b3b620d109a1d850b262",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "kernel/workqueue.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "4.5"
            },
            {
              "lessThan": "4.5",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "5.10.*",
              "status": "unaffected",
              "version": "5.10.271",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "5.15.*",
              "status": "unaffected",
              "version": "5.15.222",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.1.*",
              "status": "unaffected",
              "version": "6.1.189",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.6.*",
              "status": "unaffected",
              "version": "6.6.158",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.112",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.55",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.2.*",
              "status": "unaffected",
              "version": "7.2.9",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.3",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "5.10.271",
                  "versionStartIncluding": "4.5",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "5.15.222",
                  "versionStartIncluding": "4.5",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.1.189",
                  "versionStartIncluding": "4.5",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.6.158",
                  "versionStartIncluding": "4.5",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.12.112",
                  "versionStartIncluding": "4.5",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.18.55",
                  "versionStartIncluding": "4.5",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.2.9",
                  "versionStartIncluding": "4.5",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.3",
                  "versionStartIncluding": "4.5",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nworkqueue: Fix NULL current_pwq deref in flush dependency check\n\ncheck_flush_dependency() uses current_wq_worker() to determine whether\nthe caller is a workqueue worker and then dereferences worker-\u003ecurrent_pwq\nto test whether the current workqueue is WQ_MEM_RECLAIM.\n\ncurrent_wq_worker() only means that %current has PF_WQ_WORKER set. A\nkworker can reach check_flush_dependency() while it is not executing a\nwork item. One such path is worker_thread() acting as the pool manager,\nwhere create_worker() does GFP_KERNEL allocation and the allocation path\ninvokes the OOM notifier. In that state worker-\u003ecurrent_pwq is NULL\nbecause current_pwq is set only by process_one_work() and cleared again\nafter the work function returns.\n\n[  416.760634][  T375] Call trace:\n[  416.760638][  T375]  check_flush_dependency+0x80/0x120 (P)\n[  416.760648][  T375]  __flush_work+0x98/0x224\n[  416.760657][  T375]  flush_work+0x30/0x44\n[  416.760665][  T375]  ...\n[  416.760710][  T375]  blocking_notifier_call_chain+0x58/0xa0\n[  416.760719][  T375]  out_of_memory+0xb4/0x458\n[  416.760730][  T375]  __alloc_pages_may_oom+0x11c/0x1a8\n[  416.760739][  T375]  __alloc_pages_slowpath+0x314/0x46c\n[  416.760746][  T375]  __alloc_frozen_pages_noprof+0x110/0x1a4\n[  416.760753][  T375]  new_slab+0x12c/0x484\n[  416.760759][  T375]  ___slab_alloc+0x7a8/0xc7c\n[  416.760765][  T375]  __slab_alloc+0x74/0xd8\n[  416.760772][  T375]  __kmalloc_cache_node_noprof+0x2ac/0x304\n[  416.760779][  T375]  alloc_worker+0x28/0x60\n[  416.760785][  T375]  create_worker+0x4c/0x20c\n[  416.760790][  T375]  worker_thread+0xe8/0x2b8\n[  416.760796][  T375]  kthread+0x1a8/0x200\n[  416.760805][  T375]  ret_from_fork+0x10/0x20\n\nGuard the WQ_MEM_RECLAIM-worker warning with worker-\u003ecurrent_pwq. If the\nkworker is not currently executing a work item, there is no current\nworkqueue to diagnose with that warning. The PF_MEMALLOC warning is left\nunchanged so explicit reclaim context flushing a !WQ_MEM_RECLAIM target\nis still reported."
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-10-19T09:21:20.715Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/8ffececcb88262389b4f91fed0fe4884b68204bc"
        },
        {
          "url": "https://git.kernel.org/stable/c/9bb739a5c5a570c28a62afb98e9326e2a49743c1"
        },
        {
          "url": "https://git.kernel.org/stable/c/cc190a6a1d20b87e6a9435202fc2a3bd84c79fb3"
        },
        {
          "url": "https://git.kernel.org/stable/c/513121e69388604619ea8c0ee07e86a3d1b5b5dc"
        },
        {
          "url": "https://git.kernel.org/stable/c/0c6b9b1e295aeff1132ac7aa738148cc65f06485"
        },
        {
          "url": "https://git.kernel.org/stable/c/1dccf5dc2f8fe688270b261ca4216e03c6a1e674"
        },
        {
          "url": "https://git.kernel.org/stable/c/f97e6d0572d1b39998e053732332bc3cfdd0b9aa"
        },
        {
          "url": "https://git.kernel.org/stable/c/db6365ced4d5855e321f772b240c0e473bcfcdd5"
        }
      ],
      "title": "workqueue: Fix NULL current_pwq deref in flush dependency check",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-98537",
    "datePublished": "2026-10-18T15:18:05.028Z",
    "dateReserved": "2026-09-25T10:25:14.355Z",
    "dateUpdated": "2026-10-19T09:21:20.715Z",
    "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.

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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.
Browse all ATT&CK techniques and the vulnerabilities related to each.

Related by attack behaviour

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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