CVE-2026-98820 (GCVE-0-2026-98820)

Vulnerability from cvelistv5 – Published: 2026-10-18 15:49 – Updated: 2026-10-19 09:26
VLAI
Title
blk-mq: set RQF_USE_SCHED when the operation is known
Summary
In the Linux kernel, the following vulnerability has been resolved: blk-mq: set RQF_USE_SCHED when the operation is known The cached requests are allocated for one operation but can be handed out for another. A passthrough command has RQF_USE_SCHED cleared, so using those flags for a subsequent read/write bio will insert it into the scheduler without ->prepare_request() and frees it without ->finish_request(). For kyber, this leaks the domain token acquired at dispatch and stalls the queue. Don't set RQF_USE_SCHED based on the first operation the batch happened to be allocated for. Instead, set it after the request is claimed by an operation. Introduce a helper function, blk_mq_rq_late_init() for this, and absorb blk_mq_rq_time_init() since the two run together.
Severity
No CVSS data available.
Assigner
Linux CNA under the mitre root
CNA scorecard D 53/100 over 7067 records in the last 180 days details
References
Impacted products
Vendor Product Version CPE status
Linux Linux Affected: 4b6a5d9cea911424e84107df8c4eb8317938d2cd , < 790730e4d95de8356a573d4b4864486bba731863 (git)
Affected: 4b6a5d9cea911424e84107df8c4eb8317938d2cd , < 2c47ebc27fa72078e26177cd458cdaf3006a9685 (git)
Affected: 4b6a5d9cea911424e84107df8c4eb8317938d2cd , < ab6c756f28c741d704a7c3e04814bfc3adf6f818 (git)
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Linux Linux Affected: 6.1
Unaffected: 0 , < 6.1 (semver)
Unaffected: 6.18.56 , ≤ 6.18.* (semver)
Unaffected: 7.2.10 , ≤ 7.2.* (semver)
Unaffected: 7.3 , ≤ * (original_commit_for_fix)
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Show details on NVD website
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{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "block/blk-mq.c",
            "block/mq-deadline.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
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          "vendor": "Linux",
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      "cpeApplicability": [
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                  "vulnerable": true
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                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nblk-mq: set RQF_USE_SCHED when the operation is known\n\nThe cached requests are allocated for one operation but can be handed\nout for another. A passthrough command has RQF_USE_SCHED cleared, so\nusing those flags for a subsequent read/write bio will insert it into\nthe scheduler without -\u003eprepare_request() and frees it without\n-\u003efinish_request(). For kyber, this leaks the domain token acquired at\ndispatch and stalls the queue.\n\nDon\u0027t set RQF_USE_SCHED based on the first operation the batch happened\nto be allocated for. Instead, set it after the request is claimed by an\noperation. Introduce a helper function, blk_mq_rq_late_init() for this,\nand absorb blk_mq_rq_time_init() since the two run together."
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-10-19T09:26:13.210Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
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          "url": "https://git.kernel.org/stable/c/790730e4d95de8356a573d4b4864486bba731863"
        },
        {
          "url": "https://git.kernel.org/stable/c/2c47ebc27fa72078e26177cd458cdaf3006a9685"
        },
        {
          "url": "https://git.kernel.org/stable/c/ab6c756f28c741d704a7c3e04814bfc3adf6f818"
        }
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      "title": "blk-mq: set RQF_USE_SCHED when the operation is known",
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  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-98820",
    "datePublished": "2026-10-18T15:49:12.251Z",
    "dateReserved": "2026-09-25T10:25:14.372Z",
    "dateUpdated": "2026-10-19T09:26:13.210Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2",
  "vulnerability-lookup:meta": {
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      "date": "2026-10-26",
      "epss": "0.00206",
      "percentile": "0.10635"
    },
    "microsoft_vex": {
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      "cve": "CVE-2026-98820",
      "id": "msrc_CVE-2026-98820",
      "initial_release_date": "2026-10-20T01:03:52.000Z",
      "product_status:known_affected": "1",
      "product_status:under_investigation": "1",
      "source": "Microsoft CSAF VEX",
      "status": "final",
      "title": "blk-mq: set RQF_USE_SCHED when the operation is known",
      "url": "https://msrc.microsoft.com/csaf/vex/2026/msrc_cve-2026-98820.json",
      "version": "3"
    },
    "nvd": {
      "cve": {
        "affected": [
          {
            "affectedData": [
              {
                "defaultStatus": "unaffected",
                "product": "Linux",
                "programFiles": [
                  "block/blk-mq.c",
                  "block/mq-deadline.c"
                ],
                "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
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                "vendor": "Linux",
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                    "versionType": "semver"
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            ],
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
          }
        ],
        "cveTags": [],
        "descriptions": [
          {
            "lang": "en",
            "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nblk-mq: set RQF_USE_SCHED when the operation is known\n\nThe cached requests are allocated for one operation but can be handed\nout for another. A passthrough command has RQF_USE_SCHED cleared, so\nusing those flags for a subsequent read/write bio will insert it into\nthe scheduler without -\u003eprepare_request() and frees it without\n-\u003efinish_request(). For kyber, this leaks the domain token acquired at\ndispatch and stalls the queue.\n\nDon\u0027t set RQF_USE_SCHED based on the first operation the batch happened\nto be allocated for. Instead, set it after the request is claimed by an\noperation. Introduce a helper function, blk_mq_rq_late_init() for this,\nand absorb blk_mq_rq_time_init() since the two run together."
          }
        ],
        "id": "CVE-2026-98820",
        "lastModified": "2026-10-19T10:19:46.087",
        "metrics": {},
        "published": "2026-10-18T16:17:36.240",
        "references": [
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            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
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        "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "vulnStatus": "Received"
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      "cve": "CVE-2026-98820",
      "id": "CVE-2026-98820",
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      "product_status:known_affected": "187",
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      "source": "Red Hat CSAF VEX",
      "status": "final",
      "title": "kernel: blk-mq: set RQF_USE_SCHED when the operation is known",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-98820.json",
      "version": "3"
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      "id": "CVE-2026-98820",
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      "url": "https://ftp.suse.com/pub/projects/security/csaf-vex/2026/cve-2026-98820.json",
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    }
  }
}



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