sched_ext: Remove redundant css_put() in scx_cgroup_init()

{
  "id": "cbdf1a168d642b4300351b59ebb86a0b0708ff7d2ccc2885c85fa4bc90e81527",
  "url": "https://osv.dev/vulnerability/CVE-2026-43438",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "sched_ext: Remove redundant css_put() in scx_cgroup_init()",
    "summary": "In the Linux kernel, the following vulnerability has been resolved: sched_ext: Remove redundant css_put() in scx_cgroup_init() The iterator css_for_each_descendant_pre() walks the cgroup hierarchy under cgroup_lock(). It does not increment the reference counts on yielded css structs. According to the cgroup documentation, css_put() should only be used to release a reference obtained via css_get() or css_tryget_online(). Since the iterator does not use either of these to acquire a reference, calling css_put() in the error path of scx_cgroup_init() causes a refcount underflow. Remove the unbalanced css_put() to prevent a potential Use-After-Free (UAF) vulnerability.",
    "evidence": "osv:CVE-2026-43438",
    "products": [
      {
        "name": {
          "value": "Kernel",
          "evidence": "/affected/1/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "6.12.78",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "6.18.19",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "6.19.9",
            "evidence": "/affected/1/ranges"
          }
        ],
        "affected_versions": []
      }
    ],
    "severity": "high",
    "structured": {
      "id": "CVE-2026-43438",
      "aliases": [
        "CVE-2026-43438"
      ],
      "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": "8195136669661fdfe54e9a8923c33b31c92fc1da"
                },
                {
                  "fixed": "cc095cd305fddbe25a968e4a78436ff9476cf0f6"
                },
                {
                  "fixed": "6eaaa67d6998f6c30c462b140db8c062e07ec473"
                },
                {
                  "fixed": "bf50f3285eda8a0173625fcdb5f183f96e1008cd"
                },
                {
                  "fixed": "1336b579f6079fb8520be03624fcd9ba443c930b"
                }
              ]
            }
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-43438.json"
          }
        },
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "6.12.0"
                },
                {
                  "fixed": "6.12.78"
                }
              ]
            },
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "6.13.0"
                },
                {
                  "fixed": "6.18.19"
                }
              ]
            },
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "6.19.0"
                },
                {
                  "fixed": "6.19.9"
                }
              ]
            }
          ],
          "package": {
            "name": "Kernel",
            "ecosystem": "Linux"
          },
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-43438.json"
          }
        }
      ],
      "modified": "2026-10-28T02:30:29.720081351Z",
      "provider": "osv",
      "references": [
        "https://git.kernel.org/stable/c/1336b579f6079fb8520be03624fcd9ba443c930b",
        "https://git.kernel.org/stable/c/6eaaa67d6998f6c30c462b140db8c062e07ec473",
        "https://git.kernel.org/stable/c/bf50f3285eda8a0173625fcdb5f183f96e1008cd",
        "https://git.kernel.org/stable/c/cc095cd305fddbe25a968e4a78436ff9476cf0f6",
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/43xxx/CVE-2026-43438.json",
        "https://nvd.nist.gov/vuln/detail/CVE-2026-43438",
        "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/2026/43xxx/CVE-2026-43438.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-43438",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 496483,
  "published_at": "2026-05-08T14:22:07.98+00:00"
}