cxl/features: Serialize multi-part Get/Set Feature transfers

{
  "id": "897af36189dab0ea7b0f0b0fe982a2c1e8b971f2703de453b52f72a9e7ef0ad2",
  "url": "https://osv.dev/vulnerability/CVE-2026-93096",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "cxl/features: Serialize multi-part Get/Set Feature transfers",
    "summary": "In the Linux kernel, the following vulnerability has been resolved: cxl/features: Serialize multi-part Get/Set Feature transfers A Get or Set Feature payload larger than the mailbox payload size is split into several mailbox commands. mbox_mutex only serializes individual mailbox commands and is dropped between iterations of these loops. Nothing serializes the multi-part transfer as a whole. cxl_get_feature() and cxl_set_feature() are reachable concurrently from fwctl (per-fd RPCs run under a read-held registration lock) and from the EDAC scrub/ECS/repair paths, so two transfers to the same mailbox can interleave their parts and corrupt the device's transfer context. Add a per-mailbox feat_mutex and hold it across the whole transfer in both functions. It nests outside mbox_mutex (which is taken inside cxl_internal_send_cmd()), and is taken nowhere else, so no lock-ordering inversion is introduced.",
    "evidence": "osv:CVE-2026-93096",
    "products": [
      {
        "name": {
          "value": "Kernel",
          "evidence": "/affected/1/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "6.18.57",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "7.2.6",
            "evidence": "/affected/1/ranges"
          }
        ],
        "affected_versions": []
      }
    ],
    "severity": "unknown",
    "structured": {
      "id": "CVE-2026-93096",
      "aliases": [
        "CVE-2026-93096"
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
              "type": "GIT",
              "events": [
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                  "introduced": "5e5ac21f629de796ab5d598b59c5e468c6fe4f95"
                },
                {
                  "fixed": "c6492e17412048387435f256ffafc4dd6518db28"
                },
                {
                  "fixed": "7682b617db1f19bc606b5f1badadcf1e63a87b14"
                },
                {
                  "fixed": "77b814c1832fde018c30357b4ec3fcdaa91a1c10"
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            }
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-93096.json"
          }
        },
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "6.15.0"
                },
                {
                  "fixed": "6.18.57"
                }
              ]
            },
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "6.19.0"
                },
                {
                  "fixed": "7.2.6"
                }
              ]
            }
          ],
          "package": {
            "name": "Kernel",
            "ecosystem": "Linux"
          },
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-93096.json"
          }
        }
      ],
      "modified": "2026-10-28T02:30:52.745848123Z",
      "provider": "osv",
      "references": [
        "https://git.kernel.org/stable/c/7682b617db1f19bc606b5f1badadcf1e63a87b14",
        "https://git.kernel.org/stable/c/77b814c1832fde018c30357b4ec3fcdaa91a1c10",
        "https://git.kernel.org/stable/c/c6492e17412048387435f256ffafc4dd6518db28",
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/93xxx/CVE-2026-93096.json",
        "https://nvd.nist.gov/vuln/detail/CVE-2026-93096",
        "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/2026/93xxx/CVE-2026-93096.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-93096",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": null
  },
  "source_id": "core-osv",
  "document_id": 521779,
  "published_at": "2026-09-17T16:11:10.359+00:00"
}