vsock/virtio: fix potential underflow in virtio_transport_get_credit()

{
  "id": "299085dc0bdaa4e125a627e943eed2e4b4695040eb0ff54fa88dd4e07b4f3fab",
  "url": "https://osv.dev/vulnerability/CVE-2026-23069",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "vsock/virtio: fix potential underflow in virtio_transport_get_credit()",
    "summary": "In the Linux kernel, the following vulnerability has been resolved: vsock/virtio: fix potential underflow in virtio_transport_get_credit() The credit calculation in virtio_transport_get_credit() uses unsigned arithmetic: ret = vvs->peer_buf_alloc - (vvs->tx_cnt - vvs->peer_fwd_cnt); If the peer shrinks its advertised buffer (peer_buf_alloc) while bytes are in flight, the subtraction can underflow and produce a large positive value, potentially allowing more data to be queued than the peer can handle. Reuse virtio_transport_has_space() which already handles this case and add a comment to make it clear why we are doing that. [Stefano: use virtio_transport_has_space() instead of duplicating the code] [Stefano: tweak the commit message]",
    "evidence": "osv:CVE-2026-23069",
    "products": [
      {
        "name": {
          "value": "Kernel",
          "evidence": "/affected/1/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "6.1.162",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "6.6.122",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "6.12.68",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "6.18.8",
            "evidence": "/affected/1/ranges"
          }
        ],
        "affected_versions": []
      }
    ],
    "severity": "unknown",
    "structured": {
      "id": "CVE-2026-23069",
      "aliases": [
        "CVE-2026-23069"
      ],
      "affected": [
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              "type": "GIT",
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                {
                  "fixed": "d96de882d6b99955604669d962ae14e94b66a551"
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                  "fixed": "02f9af192b98d15883c70dd41ac76d1b0217c899"
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            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-23069.json"
          }
        },
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
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                {
                  "introduced": "4.8.0"
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              ]
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            {
              "type": "ECOSYSTEM",
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                  "introduced": "6.2.0"
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              "type": "ECOSYSTEM",
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                  "introduced": "6.13.0"
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          "package": {
            "name": "Kernel",
            "ecosystem": "Linux"
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          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-23069.json"
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      ],
      "modified": "2026-10-28T02:30:40.110366724Z",
      "provider": "osv",
      "references": [
        "https://git.kernel.org/stable/c/02f9af192b98d15883c70dd41ac76d1b0217c899",
        "https://git.kernel.org/stable/c/3ef3d52a1a9860d094395c7a3e593f3aa26ff012",
        "https://git.kernel.org/stable/c/d05bc313788f0684b27f0f5b60c52a844669b542",
        "https://git.kernel.org/stable/c/d96de882d6b99955604669d962ae14e94b66a551",
        "https://git.kernel.org/stable/c/ec0f1b3da8061be3173d1c39faaf9504f91942c3",
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/23xxx/CVE-2026-23069.json",
        "https://nvd.nist.gov/vuln/detail/CVE-2026-23069",
        "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/2026/23xxx/CVE-2026-23069.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-23069",
        "evidence": "/id"
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    "security_relevant": true,
    "severity_evidence": null
  },
  "source_id": "core-osv",
  "document_id": 507756,
  "published_at": "2026-02-04T16:07:49.911+00:00"
}