vhost-scsi: reject feature changes after endpoint

{
  "id": "34a7d9e0a184128318597cc26df40b40b8fe2cf86fea93b1baf53de3fd1bbdd6",
  "url": "https://osv.dev/vulnerability/CVE-2026-74702",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "vhost-scsi: reject feature changes after endpoint",
    "summary": "In the Linux kernel, the following vulnerability has been resolved: vhost-scsi: reject feature changes after endpoint vhost_scsi_setup_vq_cmds() runs from VHOST_SCSI_SET_ENDPOINT and allocates each command's protection scatterlist array (prot_sgl) according to the acknowledged VIRTIO_SCSI_F_T10_PI bit. The command pools are not rebuilt when VHOST_SET_FEATURES changes that bit later. Although virtio feature bits must not change after feature negotiation, vhost_scsi_set_features() currently accepts such a request after the endpoint is active and updates acked_features. Enabling T10-PI after endpoint setup therefore leaves prot_sgl NULL while the I/O path follows the new feature bit. For a 129-page protection payload, vhost_scsi_mapal() passes the missing first chunk to sg_alloc_table_chained(): sg_alloc_table_chained(table, 129, first_chunk=NULL, nents_first_chunk=inline_sg_cnt) sg_pool_index() then hits: BUG_ON(nents > SG_CHUNK_SIZE); /* 129 > 128 */ The kernel reported the following call trace and register state: Call Trace: ? __sg_alloc_table+0x1d8/0x250 ? __pfx_vhost_run_work_list+0x10/0x10 [vhost] sg_alloc_table_chained+0x59/0xf0 ? __pfx_sg_pool_alloc+0x10/0x10 ? vhost_scsi_calc_sgls.constprop.0+0x43/0x60 [vhost_scsi] vhost_scsi_handle_vq+0xf02/0x1700 [vhost_scsi] ? __pfx_vhost_scsi_handle_vq+0x10/0x10 [vhost_scsi] vhost_scsi_handle_kick+0x37/0x50 [vhost_scsi] vhost_run_work_list+0x8e/0xd0 [vhost] vhost_task_fn+0xe1/0x210 ret_from_fork+0x348/0x540 RIP: 0010:0x4 CR2 = 0x4 R",
    "evidence": "osv:CVE-2026-74702",
    "products": [
      {
        "name": {
          "value": "Kernel",
          "evidence": "/affected/1/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "6.18.45",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "7.1.9",
            "evidence": "/affected/1/ranges"
          }
        ],
        "affected_versions": []
      }
    ],
    "severity": "high",
    "structured": {
      "id": "CVE-2026-74702",
      "aliases": [
        "CVE-2026-74702"
      ],
      "metrics": [
        {
          "type": "CVSS_V3",
          "score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/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": "bf2d650391be508dd8b5e188b65ed32300cf3489"
                },
                {
                  "fixed": "a06e4611d45518896fbff4f45d9581578b107e91"
                },
                {
                  "fixed": "9a3eb77a612f9d158e4d27df43677a014e9cfa55"
                },
                {
                  "fixed": "42bc45df5905e2b7dccb72adaf7730f66cfbe03f"
                }
              ]
            }
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-74702.json"
          }
        },
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "6.15.0"
                },
                {
                  "fixed": "6.18.45"
                }
              ]
            },
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "6.19.0"
                },
                {
                  "fixed": "7.1.9"
                }
              ]
            }
          ],
          "package": {
            "name": "Kernel",
            "ecosystem": "Linux"
          },
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-74702.json"
          }
        }
      ],
      "modified": "2026-10-28T02:30:49.056709146Z",
      "provider": "osv",
      "references": [
        "https://git.kernel.org/stable/c/42bc45df5905e2b7dccb72adaf7730f66cfbe03f",
        "https://git.kernel.org/stable/c/9a3eb77a612f9d158e4d27df43677a014e9cfa55",
        "https://git.kernel.org/stable/c/a06e4611d45518896fbff4f45d9581578b107e91",
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/74xxx/CVE-2026-74702.json",
        "https://nvd.nist.gov/vuln/detail/CVE-2026-74702",
        "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/2026/74xxx/CVE-2026-74702.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-74702",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 517232,
  "published_at": "2026-08-22T15:33:02.223+00:00"
}