sched_ext: Validate prev_cpu in scx_bpf_select_cpu_dfl()

{
  "id": "7bac685843e7589047d2597cb02e384397c0f72a87dd966a3572ff54948296bb",
  "url": "https://osv.dev/vulnerability/CVE-2025-21965",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "sched_ext: Validate prev_cpu in scx_bpf_select_cpu_dfl()",
    "summary": "In the Linux kernel, the following vulnerability has been resolved: sched_ext: Validate prev_cpu in scx_bpf_select_cpu_dfl() If a BPF scheduler provides an invalid CPU (outside the nr_cpu_ids range) as prev_cpu to scx_bpf_select_cpu_dfl() it can cause a kernel crash. To prevent this, validate prev_cpu in scx_bpf_select_cpu_dfl() and trigger an scx error if an invalid CPU is specified.",
    "evidence": "osv:CVE-2025-21965",
    "products": [
      {
        "name": {
          "value": "Kernel",
          "evidence": "/affected/1/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "6.12.20",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "6.13.8",
            "evidence": "/affected/1/ranges"
          }
        ],
        "affected_versions": []
      }
    ],
    "severity": "high",
    "structured": {
      "id": "CVE-2025-21965",
      "aliases": [
        "CVE-2025-21965"
      ],
      "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": "f0e1a0643a59bf1f922fa209cec86a170b784f3f"
                },
                {
                  "fixed": "752b56bb76e2471197d25d6948d85753043b10da"
                },
                {
                  "fixed": "515680e76c536dd4aa8e2b5d674b0d441baddf5b"
                },
                {
                  "fixed": "9360dfe4cbd62ff1eb8217b815964931523b75b3"
                }
              ]
            }
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2025-21965.json"
          }
        },
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "6.12.0"
                },
                {
                  "fixed": "6.12.20"
                }
              ]
            },
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "6.13.0"
                },
                {
                  "fixed": "6.13.8"
                }
              ]
            }
          ],
          "package": {
            "name": "Kernel",
            "ecosystem": "Linux"
          },
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2025-21965.json"
          }
        }
      ],
      "modified": "2026-10-28T02:30:51.538951799Z",
      "provider": "osv",
      "references": [
        "https://git.kernel.org/stable/c/515680e76c536dd4aa8e2b5d674b0d441baddf5b",
        "https://git.kernel.org/stable/c/752b56bb76e2471197d25d6948d85753043b10da",
        "https://git.kernel.org/stable/c/9360dfe4cbd62ff1eb8217b815964931523b75b3",
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2025/21xxx/CVE-2025-21965.json",
        "https://nvd.nist.gov/vuln/detail/CVE-2025-21965",
        "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-2025-21965.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2025-21965",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 520151,
  "published_at": "2025-04-01T15:47:01.129+00:00"
}