workqueue: Put the pwq after detaching the rescuer from the pool

{
  "id": "238c4a9783ec3cc2cbb42a59a08115bf0339011b958d86964960e2fd1bb11011",
  "url": "https://osv.dev/vulnerability/CVE-2025-21786",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "workqueue: Put the pwq after detaching the rescuer from the pool",
    "summary": "In the Linux kernel, the following vulnerability has been resolved: workqueue: Put the pwq after detaching the rescuer from the pool The commit 68f83057b913(\"workqueue: Reap workers via kthread_stop() and remove detach_completion\") adds code to reap the normal workers but mistakenly does not handle the rescuer and also removes the code waiting for the rescuer in put_unbound_pool(), which caused a use-after-free bug reported by Cheung Wall. To avoid the use-after-free bug, the pool’s reference must be held until the detachment is complete. Therefore, move the code that puts the pwq after detaching the rescuer from the pool.",
    "evidence": "osv:CVE-2025-21786",
    "products": [
      {
        "name": {
          "value": "Kernel",
          "evidence": "/affected/1/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "6.12.16",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "6.13.4",
            "evidence": "/affected/1/ranges"
          }
        ],
        "affected_versions": []
      }
    ],
    "severity": "high",
    "structured": {
      "id": "CVE-2025-21786",
      "aliases": [
        "CVE-2025-21786"
      ],
      "metrics": [
        {
          "type": "CVSS_V3",
          "score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
              "type": "GIT",
              "events": [
                {
                  "introduced": "68f83057b913467a999e1bf9e0da6a119668f769"
                },
                {
                  "fixed": "e7c16028a424dd35be1064a68fa318be4359310f"
                },
                {
                  "fixed": "835b69c868f53f959d4986bbecd561ba6f38e492"
                },
                {
                  "fixed": "e76946110137703c16423baf6ee177b751a34b7e"
                }
              ]
            }
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2025-21786.json"
          }
        },
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "6.11.0"
                },
                {
                  "fixed": "6.12.16"
                }
              ]
            },
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "6.13.0"
                },
                {
                  "fixed": "6.13.4"
                }
              ]
            }
          ],
          "package": {
            "name": "Kernel",
            "ecosystem": "Linux"
          },
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2025-21786.json"
          }
        }
      ],
      "modified": "2026-10-28T02:30:30.846434599Z",
      "provider": "osv",
      "references": [
        "https://git.kernel.org/stable/c/835b69c868f53f959d4986bbecd561ba6f38e492",
        "https://git.kernel.org/stable/c/e76946110137703c16423baf6ee177b751a34b7e",
        "https://git.kernel.org/stable/c/e7c16028a424dd35be1064a68fa318be4359310f",
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2025/21xxx/CVE-2025-21786.json",
        "https://nvd.nist.gov/vuln/detail/CVE-2025-21786",
        "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"
      ],
      "provider_metadata": {
        "cna_assigner": "Linux",
        "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2025/21xxx/CVE-2025-21786.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2025-21786",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 497886,
  "published_at": "2025-02-27T02:18:26.406+00:00"
}