CVE-2026-64232 (GCVE-0-2026-64232)
Vulnerability from cvelistv5
Published
2026-07-24 15:23
Modified
2026-08-05 12:40
Severity ?
9.8 (Critical) - CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Summary
In the Linux kernel, the following vulnerability has been resolved: block: recompute nr_integrity_segments in blk_insert_cloned_request blk_insert_cloned_request() already recomputes nr_phys_segments against the bottom queue, because "the queue settings related to segment counting may differ from the original queue." The exact same reasoning applies to integrity segments: a stacked driver's underlying queue can have tighter virt_boundary_mask, seg_boundary_mask, or max_segment_size than the top queue, in which case blk_rq_count_integrity_sg() against the bottom queue produces a different count than the cached rq->nr_integrity_segments inherited from the source request by blk_rq_prep_clone(). When the cached count is lower than the bottom queue's actual count, blk_rq_map_integrity_sg() trips BUG_ON(segments > rq->nr_integrity_segments); on dispatch. The same families of stacked setups that motivated the existing nr_phys_segments recompute -- dm-multipath fanning out to nvme-rdma in particular -- can produce this. Mirror the nr_phys_segments handling: when the request carries integrity, recompute nr_integrity_segments against the bottom queue and reject the request if it exceeds the bottom queue's max_integrity_segments. blk_rq_count_integrity_sg() and queue_max_integrity_segments() are both already available via <linux/blk-integrity.h>, which blk-mq.c includes. This closes a latent gap in the stacking contract and brings the integrity-segment accounting in line with the existing phys-segment accounting.
References
Impacted products
Vendor Product Version
Linux Linux Version: 76c313f658d2752e8527610677164aa7094ef7a5
Version: 76c313f658d2752e8527610677164aa7094ef7a5
Version: 76c313f658d2752e8527610677164aa7094ef7a5
Version: 76c313f658d2752e8527610677164aa7094ef7a5
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{
  "containers": {
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      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "block/blk-mq.c"
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          "vendor": "Linux",
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              "version": "0",
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              "version": "6.18.34",
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              "version": "7.0.11",
              "versionType": "semver"
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              "status": "unaffected",
              "version": "7.1",
              "versionType": "original_commit_for_fix"
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      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
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                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.12.92",
                  "versionStartIncluding": "6.12",
                  "vulnerable": true
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                {
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              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nblock: recompute nr_integrity_segments in blk_insert_cloned_request\n\nblk_insert_cloned_request() already recomputes nr_phys_segments\nagainst the bottom queue, because \"the queue settings related to\nsegment counting may differ from the original queue.\" The exact same\nreasoning applies to integrity segments: a stacked driver\u0027s underlying\nqueue can have tighter virt_boundary_mask, seg_boundary_mask, or\nmax_segment_size than the top queue, in which case\nblk_rq_count_integrity_sg() against the bottom queue produces a\ndifferent count than the cached rq-\u003enr_integrity_segments inherited\nfrom the source request by blk_rq_prep_clone().\n\nWhen the cached count is lower than the bottom queue\u0027s actual count,\nblk_rq_map_integrity_sg() trips\n\n\tBUG_ON(segments \u003e rq-\u003enr_integrity_segments);\n\non dispatch. The same families of stacked setups that motivated the\nexisting nr_phys_segments recompute -- dm-multipath fanning out to\nnvme-rdma in particular -- can produce this.\n\nMirror the nr_phys_segments handling: when the request carries\nintegrity, recompute nr_integrity_segments against the bottom queue\nand reject the request if it exceeds the bottom queue\u0027s\nmax_integrity_segments. blk_rq_count_integrity_sg() and\nqueue_max_integrity_segments() are both already available via\n\u003clinux/blk-integrity.h\u003e, which blk-mq.c includes.\n\nThis closes a latent gap in the stacking contract and brings the\nintegrity-segment accounting in line with the existing\nphys-segment accounting."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "baseScore": 9.8,
            "baseSeverity": "CRITICAL",
            "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
            "version": "3.1"
          },
          "scenarios": [
            {
              "lang": "en",
              "value": "AV:N - A PI-enabled iSER or NVMe/RDMA target can expose the affected request-based dm-multipath device, allowing remote storage commands to reach the vulnerable clone-dispatch path.\nAC:L - Once the affected storage topology is configured, the attacker controls the metadata-bearing I/O requests and can trigger the segment-count mismatch repeatedly without winning an uncontrollable race.\nPR:N - Targets configured with dynamic ACLs and authentication disabled, or NVMe allow_any_host, permit unauthenticated remote initiators to issue the required I/O.\nUI:N - No victim action is required after the network storage target and affected backend are operational.\nS:U - The corruption occurs within the host kernel processing the target\u0027s block I/O and does not inherently cross a separate security authority such as a guest-host boundary.\nC:H - The undersized integrity scatterlist is populated beyond its declared bounds before the BUG_ON executes, permitting adjacent kernel-memory corruption that could be leveraged for arbitrary kernel access and disclosure.\nI:H - The out-of-bounds scatterlist writes corrupt kernel memory and may permit control-flow hijacking or arbitrary modification if the attacker shapes the surrounding allocation state.\nA:H - The post-write BUG_ON reliably causes a kernel oops or panic, and malformed requests can be submitted repeatedly to disrupt the storage target."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-08-05T12:40:12.752Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/53a01bcc0242590eda4c452a5bd996f62457113b"
        },
        {
          "url": "https://git.kernel.org/stable/c/0943f81e1b3176f27dbaf6db268fc69d8a94f0ba"
        },
        {
          "url": "https://git.kernel.org/stable/c/42929c98d044f126508baf54a65b0f87f932fa75"
        },
        {
          "url": "https://git.kernel.org/stable/c/2c6e6a18a37b905cb584eb0dda3ae482162a81ca"
        }
      ],
      "title": "block: recompute nr_integrity_segments in blk_insert_cloned_request",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-64232",
    "datePublished": "2026-07-24T15:23:13.729Z",
    "dateReserved": "2026-07-19T15:36:31.771Z",
    "dateUpdated": "2026-08-05T12:40:12.752Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}


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