tracing/osnoise: Fix null-ptr-deref in bitmap_parselist()

{
  "id": "473bafbaca10150ef1c052f242566db611b1faa2aac7efa08247ba1f86c91ab5",
  "url": "https://osv.dev/vulnerability/CVE-2025-39887",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "tracing/osnoise: Fix null-ptr-deref in bitmap_parselist()",
    "summary": "In the Linux kernel, the following vulnerability has been resolved: tracing/osnoise: Fix null-ptr-deref in bitmap_parselist() A crash was observed with the following output: BUG: kernel NULL pointer dereference, address: 0000000000000010 Oops: Oops: 0000 [#1] SMP NOPTI CPU: 2 UID: 0 PID: 92 Comm: osnoise_cpus Not tainted 6.17.0-rc4-00201-gd69eb204c255 #138 PREEMPT(voluntary) RIP: 0010:bitmap_parselist+0x53/0x3e0 Call Trace: osnoise_cpus_write+0x7a/0x190 vfs_write+0xf8/0x410 ? do_sys_openat2+0x88/0xd0 ksys_write+0x60/0xd0 do_syscall_64+0xa4/0x260 entry_SYSCALL_64_after_hwframe+0x77/0x7f This issue can be reproduced by below code: fd=open(\"/sys/kernel/debug/tracing/osnoise/cpus\", O_WRONLY); write(fd, \"0-2\", 0); When user pass 'count=0' to osnoise_cpus_write(), kmalloc() will return ZERO_SIZE_PTR (16) and cpulist_parse() treat it as a normal value, which trigger the null pointer dereference. Add check for the parameter 'count'.",
    "evidence": "osv:CVE-2025-39887",
    "products": [
      {
        "name": {
          "value": "Kernel",
          "evidence": "/affected/1/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "6.16.8",
            "evidence": "/affected/1/ranges"
          }
        ],
        "affected_versions": []
      }
    ],
    "severity": "medium",
    "structured": {
      "id": "CVE-2025-39887",
      "aliases": [
        "CVE-2025-39887"
      ],
      "metrics": [
        {
          "type": "CVSS_V3",
          "score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
              "type": "GIT",
              "events": [
                {
                  "introduced": "17f89102fe23d7389085a8820550df688f79888a"
                },
                {
                  "fixed": "e33228a2cc7ff706ca88533464e8a3b525b961ed"
                },
                {
                  "fixed": "c1628c00c4351dd0727ef7f670694f68d9e663d8"
                }
              ]
            }
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2025-39887.json"
          }
        },
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "6.16.0"
                },
                {
                  "fixed": "6.16.8"
                }
              ]
            }
          ],
          "package": {
            "name": "Kernel",
            "ecosystem": "Linux"
          },
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2025-39887.json"
          }
        }
      ],
      "modified": "2026-10-28T02:30:38.074547740Z",
      "provider": "osv",
      "references": [
        "https://git.kernel.org/stable/c/c1628c00c4351dd0727ef7f670694f68d9e663d8",
        "https://git.kernel.org/stable/c/e33228a2cc7ff706ca88533464e8a3b525b961ed",
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2025/39xxx/CVE-2025-39887.json",
        "https://nvd.nist.gov/vuln/detail/CVE-2025-39887",
        "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/2025/39xxx/CVE-2025-39887.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2025-39887",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 505447,
  "published_at": "2025-09-23T06:00:53.648+00:00"
}