CVE-2026-98479 (GCVE-0-2026-98479)
Vulnerability from cvelistv5
Published
2026-10-18 15:15
Modified
2026-10-24 14:09
Severity ?
7.5 (High) - CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
Summary
In the Linux kernel, the following vulnerability has been resolved: scsi: libiscsi_tcp: Check the data direction of a Data-In PDU The Data-In branch of iscsi_tcp_hdr_dissect() resolves the ITT to a task and copies the PDU's data segment into that command's scatterlist without asking whether the command was reading. iscsi_tcp_r2t_rsp() in the same file does ask, and rejects an R2T for a command that is not DMA_TO_DEVICE. A target that answers a WRITE command's ITT with a Data-In therefore has the initiator write target-supplied bytes into the pages that write was about to send. Those are the caller's own pinned pages for an O_DIRECT write, and page cache pages for a buffered one. Observed against a test target that emits one 512-byte Data-In naming a 128 KB write's ITT, after the R2T for that write. With O_DIRECT the caller's buffer ends up holding 512 bytes of the target's data while pwrite() returns 131072. Buffered is quieter: pwrite() and fsync() both succeed, nothing is logged, and reading those blocks back returns the target's bytes out of the page cache without a command going on the wire. Check the direction before using the scatterlist, the way the R2T path already does.
References
Impacted products
Vendor Product Version
Linux Linux Version: a081c13e39b5c17052a7b46fafa61019c4c110ff
Version: a081c13e39b5c17052a7b46fafa61019c4c110ff
Version: a081c13e39b5c17052a7b46fafa61019c4c110ff
Version: a081c13e39b5c17052a7b46fafa61019c4c110ff
Version: a081c13e39b5c17052a7b46fafa61019c4c110ff
Version: a081c13e39b5c17052a7b46fafa61019c4c110ff
Version: a081c13e39b5c17052a7b46fafa61019c4c110ff
Version: a081c13e39b5c17052a7b46fafa61019c4c110ff
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{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "drivers/scsi/libiscsi_tcp.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
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          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "drivers/scsi/libiscsi_tcp.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "2.6.29"
            },
            {
              "lessThan": "2.6.29",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "5.10.*",
              "status": "unaffected",
              "version": "5.10.271",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "5.15.*",
              "status": "unaffected",
              "version": "5.15.222",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.1.*",
              "status": "unaffected",
              "version": "6.1.189",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.6.*",
              "status": "unaffected",
              "version": "6.6.158",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.112",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.55",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.2.*",
              "status": "unaffected",
              "version": "7.2.9",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.3",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
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                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "5.10.271",
                  "versionStartIncluding": "2.6.29",
                  "vulnerable": true
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                  "versionEndExcluding": "5.15.222",
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                  "vulnerable": true
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                  "versionEndExcluding": "6.1.189",
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                  "vulnerable": true
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                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.6.158",
                  "versionStartIncluding": "2.6.29",
                  "vulnerable": true
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                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.12.112",
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                  "vulnerable": true
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                {
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                  "versionEndExcluding": "6.18.55",
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                  "vulnerable": true
                },
                {
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                  "vulnerable": true
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                {
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                  "versionEndExcluding": "7.3",
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                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nscsi: libiscsi_tcp: Check the data direction of a Data-In PDU\n\nThe Data-In branch of iscsi_tcp_hdr_dissect() resolves the ITT to a task\nand copies the PDU\u0027s data segment into that command\u0027s scatterlist without\nasking whether the command was reading. iscsi_tcp_r2t_rsp() in the same\nfile does ask, and rejects an R2T for a command that is not DMA_TO_DEVICE.\n\nA target that answers a WRITE command\u0027s ITT with a Data-In therefore has\nthe initiator write target-supplied bytes into the pages that write was\nabout to send. Those are the caller\u0027s own pinned pages for an O_DIRECT\nwrite, and page cache pages for a buffered one.\n\nObserved against a test target that emits one 512-byte Data-In naming a 128\nKB write\u0027s ITT, after the R2T for that write. With O_DIRECT the caller\u0027s\nbuffer ends up holding 512 bytes of the target\u0027s data while pwrite()\nreturns 131072. Buffered is quieter: pwrite() and fsync() both succeed,\nnothing is logged, and reading those blocks back returns the target\u0027s bytes\nout of the page cache without a command going on the wire.\n\nCheck the direction before using the scatterlist, the way the R2T path\nalready does."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "baseScore": 7.5,
            "baseSeverity": "HIGH",
            "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N",
            "version": "3.1"
          },
          "scenarios": [
            {
              "lang": "en",
              "value": "AV:N - A remote iSCSI target supplies the malicious SCSI Data-In PDU over routable TCP; iscsi_sw_tcp_data_ready() reaches iscsi_tcp_recv_skb(), iscsi_tcp_hdr_dissect(), and the patched iscsi_tcp_data_in().\nAC:L - iscsi_prep_scsi_cmd_pdu() exposes the live WRITE ITT to the target, which can deterministically return a Data-In with that ITT, the expected DataSN, and an in-range offset and length; no race or outside condition is required.\nPR:N - The receive path imposes no privilege or per-PDU authentication check on the connected target; iscsi_verify_itt() only validates the ITT\u0027s session age and index, and the target learns that ITT from the WRITE command.\nUI:N - After iscsi_queuecommand() submits an ordinary WRITE on a logged-in session, the target\u0027s Data-In is processed automatically by the TCP callback; exploitation requires no user approval or opening of attacker-supplied content.\nS:U - iscsi_tcp_hdr_dissect() redirects data into task-\u003esc-\u003esdb, affecting the initiator\u0027s caller pages or page cache under the same host-kernel security authority, without crossing a VM, IOMMU, or sandbox boundary.\nC:N - iscsi_tcp_segment_recv() only copies target-supplied bytes into the command scatterlist; this defect provides no path for reading initiator memory or returning unintended bytes to the target.\nI:H - iscsi_segment_seek_sg() makes the receive segment reference a WRITE command\u0027s sdb, after which iscsi_tcp_segment_recv() copies attacker-chosen bytes into an O_DIRECT caller buffer or buffered-write page-cache pages.\nA:N - iscsi_tcp_data_in() bounds the offset and DataSegmentLength to sdb.length, and iscsi_segment_seek_sg() rejects offsets outside the scatterlist; the demonstrated effect is silent bounded data corruption, not an oops, hang, or resource exhaustion."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-10-24T14:09:01.805Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/79991b770fc3685b1d5cf805b659a879edd19931"
        },
        {
          "url": "https://git.kernel.org/stable/c/8db1232945bc663fb94f300090a1fc108de99296"
        },
        {
          "url": "https://git.kernel.org/stable/c/94e5bdd08e51c450d954bc592f591c233ca5c9df"
        },
        {
          "url": "https://git.kernel.org/stable/c/de96dc11aee0d058927bff94a168e3c5c46483e2"
        },
        {
          "url": "https://git.kernel.org/stable/c/e3b25bf2cf2496e85bc05b33360faf9fdf880e03"
        },
        {
          "url": "https://git.kernel.org/stable/c/ee56b5e18f566c0b5a183379dcd63d402cebf2f8"
        },
        {
          "url": "https://git.kernel.org/stable/c/24ffc919467d20951f0f132d1c75294e2e91e09b"
        },
        {
          "url": "https://git.kernel.org/stable/c/bce07e2f37b5e4a427d36fd6b1c14067b27591db"
        }
      ],
      "title": "scsi: libiscsi_tcp: Check the data direction of a Data-In PDU",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-98479",
    "datePublished": "2026-10-18T15:15:53.663Z",
    "dateReserved": "2026-09-25T10:25:14.351Z",
    "dateUpdated": "2026-10-24T14:09:01.805Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}


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