block: don't overwrite bip_vcnt in bio_integrity_copy_user()

{
  "id": "086dfb9b80ecf62e1e3b093e978d0b870d4ad0ada53c877c2713c8da0935094d",
  "url": "https://osv.dev/vulnerability/CVE-2026-64053",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "block: don't overwrite bip_vcnt in bio_integrity_copy_user()",
    "summary": "In the Linux kernel, the following vulnerability has been resolved: block: don't overwrite bip_vcnt in bio_integrity_copy_user() bio_integrity_add_page() already sets bip_vcnt to 1 for the bounce segment. Overwriting it with nr_vecs breaks bip_vcnt <= bip_max_vcnt on WRITE (bip_max_vcnt is 1), so the gap-merge checks in block/blk.h read past the bip_vec[] flex array. On READ the read is in bounds but lands on a saved user bvec instead of the bounce. The line was added for split propagation, but bio_integrity_clone() doesn't copy bip_vcnt and BIP_CLONE_FLAGS excludes BIP_COPY_USER.",
    "evidence": "osv:CVE-2026-64053",
    "products": [
      {
        "name": {
          "value": "Kernel",
          "evidence": "/affected/1/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "6.12.92",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "6.18.34",
            "evidence": "/affected/1/ranges"
          },
          {
            "value": "7.0.11",
            "evidence": "/affected/1/ranges"
          }
        ],
        "affected_versions": []
      }
    ],
    "severity": "high",
    "structured": {
      "id": "CVE-2026-64053",
      "aliases": [
        "CVE-2026-64053"
      ],
      "metrics": [
        {
          "type": "CVSS_V3",
          "score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
              "type": "GIT",
              "events": [
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                  "introduced": "3991657ae7074c3c497bf095093178bed37ea1b4"
                },
                {
                  "fixed": "d18160c9525c63c203656fefd847e94b538cd4a4"
                },
                {
                  "fixed": "0d48654af4d1390c888389206cc13b51b82c30e6"
                },
                {
                  "fixed": "066be1439593a381b1a29663becfcfe0c92363e7"
                },
                {
                  "fixed": "637ad3a56a3b889527d1dacea6fea2a8bd648140"
                }
              ]
            }
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-64053.json"
          }
        },
        {
          "ranges": [
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "6.11.0"
                },
                {
                  "fixed": "6.12.92"
                }
              ]
            },
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "6.13.0"
                },
                {
                  "fixed": "6.18.34"
                }
              ]
            },
            {
              "type": "ECOSYSTEM",
              "events": [
                {
                  "introduced": "6.19.0"
                },
                {
                  "fixed": "7.0.11"
                }
              ]
            }
          ],
          "package": {
            "name": "Kernel",
            "ecosystem": "Linux"
          },
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-64053.json"
          }
        }
      ],
      "modified": "2026-10-28T02:30:51.165621046Z",
      "provider": "osv",
      "references": [
        "https://git.kernel.org/stable/c/066be1439593a381b1a29663becfcfe0c92363e7",
        "https://git.kernel.org/stable/c/0d48654af4d1390c888389206cc13b51b82c30e6",
        "https://git.kernel.org/stable/c/637ad3a56a3b889527d1dacea6fea2a8bd648140",
        "https://git.kernel.org/stable/c/d18160c9525c63c203656fefd847e94b538cd4a4",
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/64xxx/CVE-2026-64053.json",
        "https://nvd.nist.gov/vuln/detail/CVE-2026-64053",
        "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/2026/64xxx/CVE-2026-64053.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-64053",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 519956,
  "published_at": "2026-07-19T15:39:35.854+00:00"
}