vsock/bpf: return early if transport is not assigned

{
  "id": "0c70666ae7d476df276a16516300b196cee371809e5fd0d17f0cee8ebe201756",
  "url": "https://osv.dev/vulnerability/CVE-2025-21670",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "vsock/bpf: return early if transport is not assigned",
    "summary": "In the Linux kernel, the following vulnerability has been resolved: vsock/bpf: return early if transport is not assigned Some of the core functions can only be called if the transport has been assigned. As Michal reported, a socket might have the transport at NULL, for example after a failed connect(), causing the following trace: BUG: kernel NULL pointer dereference, address: 00000000000000a0 #PF: supervisor read access in kernel mode #PF: error_code(0x0000) - not-present page PGD 12faf8067 P4D 12faf8067 PUD 113670067 PMD 0 Oops: Oops: 0000 [#1] PREEMPT SMP NOPTI CPU: 15 UID: 0 PID: 1198 Comm: a.out Not tainted 6.13.0-rc2+ RIP: 0010:vsock_connectible_has_data+0x1f/0x40 Call Trace: vsock_bpf_recvmsg+0xca/0x5e0 sock_recvmsg+0xb9/0xc0 __sys_recvfrom+0xb3/0x130 __x64_sys_recvfrom+0x20/0x30 do_syscall_64+0x93/0x180 entry_SYSCALL_64_after_hwframe+0x76/0x7e So we need to check the `vsk->transport` in vsock_bpf_recvmsg(), especially for connected sockets (stream/seqpacket) as we already do in __vsock_connectible_recvmsg().",
    "evidence": "osv:CVE-2025-21670",
    "products": [
      {
        "name": {
          "value": "Kernel",
          "evidence": "/affected/1/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "6.6.74",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "6.12.11",
            "evidence": "/affected/1/ranges"
          }
        ],
        "affected_versions": []
      }
    ],
    "severity": "medium",
    "structured": {
      "id": "CVE-2025-21670",
      "aliases": [
        "CVE-2025-21670"
      ],
      "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": "634f1a7110b439c65fd8a809171c1d2d28bcea6f"
                },
                {
                  "fixed": "58e586c30d0b6f5dc0174a41026f2b0a48c9aab6"
                },
                {
                  "fixed": "6771e1279dadf1d92a72e1465134257d9e6f2459"
                },
                {
                  "fixed": "f6abafcd32f9cfc4b1a2f820ecea70773e26d423"
                }
              ]
            }
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2025-21670.json"
          }
        },
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "6.4.0"
                },
                {
                  "fixed": "6.6.74"
                }
              ]
            },
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "6.7.0"
                },
                {
                  "fixed": "6.12.11"
                }
              ]
            }
          ],
          "package": {
            "name": "Kernel",
            "ecosystem": "Linux"
          },
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2025-21670.json"
          }
        }
      ],
      "modified": "2026-10-28T02:30:33.188199012Z",
      "provider": "osv",
      "references": [
        "https://git.kernel.org/stable/c/58e586c30d0b6f5dc0174a41026f2b0a48c9aab6",
        "https://git.kernel.org/stable/c/6771e1279dadf1d92a72e1465134257d9e6f2459",
        "https://git.kernel.org/stable/c/f6abafcd32f9cfc4b1a2f820ecea70773e26d423",
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2025/21xxx/CVE-2025-21670.json",
        "https://nvd.nist.gov/vuln/detail/CVE-2025-21670",
        "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-2025-21670.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2025-21670",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 500302,
  "published_at": "2025-01-31T11:25:33.874+00:00"
}