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scsi: libiscsi_tcp: Bound SCSI Response data segment to the connection buffer

Type: advisorySource: Official CVE List1 source record

In the Linux kernel, the following vulnerability has been resolved: scsi: libiscsi_tcp: Bound SCSI Response data segment to the connection buffer iscsi_tcp_hdr_dissect() receives the data segment of several PDU types into the fixed-size conn->data buffer, which is allocated for ISCSI_DEF_MAX_RECV_SEG_LEN (8192) bytes. For the LOGIN_RSP, TEXT_RSP, REJECT and ASYNC_EVENT opcodes the dissect path already rejects a PDU whose DataSegmentLength exceeds that buffer. The SCSI Command Response (ISCSI_OP_SCSI_CMD_RSP) path also copies its data segment (sense/response data) into conn->data via iscsi_tcp_data_recv_prep(), but it does so without the same check. The only upstream bound on in.datalen is conn->max_recv_dlength, the initiator's advertised MaxRecvDataSegmentLength, which is commonly negotiated well above 8192 (open-iscsi defaults to 262144). A target that returns a SCSI Response with a DataSegmentLength between 8193 and max_recv_dlength therefore overflows the 8192-byte conn->data buffer. Once the same bound applies, ISCSI_OP_SCSI_CMD_RSP is handled exactly like those responses: bound the data segment, receive it into conn->data when present, and otherwise complete the PDU with no data. Fold the opcode into that case group rather than duplicating the check.

Announced Source revision 1
Original source ↗

CVE-2026-74556

Primary source · Revision 1

Imported from structured advisory data. Source references identify upstream records or fields; verify affected versions and your deployed configuration.

Security context

Source reference: cve:CVE-2026-74556

Linux

Source reference: /containers/cna/affected/0/product

Affected versions
Not stated in this record
Fixed versions
Not stated in this record
Prerequisites
Not stated in this record

Linux

Source reference: /containers/cna/affected/1/product

Affected versions
Not stated in this record
Fixed versions
Not stated in this record
Prerequisites
Not stated in this record

Structured affected-version data

Original package identities and version rules from this source.

[
  {
    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
    "vendor": "Linux",
    "product": "Linux",
    "versions": [
      {
        "status": "affected",
        "version": "a081c13e39b5c17052a7b46fafa61019c4c110ff",
        "lessThan": "a51812842084fd390590ab8dc0431f10c73ddc56",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "a081c13e39b5c17052a7b46fafa61019c4c110ff",
        "lessThan": "a8f94cc9f0e5759252551be3a172960c57f21f54",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "a081c13e39b5c17052a7b46fafa61019c4c110ff",
        "lessThan": "f1a3a51fc5dba0e99532379665069f1700da6b44",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "a081c13e39b5c17052a7b46fafa61019c4c110ff",
        "lessThan": "c97b5265cc47775f77fd2a23d6bde0426997b233",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "a081c13e39b5c17052a7b46fafa61019c4c110ff",
        "lessThan": "084af0253673425ce2ae62e3c7f74f0dd023711b",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "a081c13e39b5c17052a7b46fafa61019c4c110ff",
        "lessThan": "72815741715bd41556dac5eeb068bf0f8af06ee7",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "a081c13e39b5c17052a7b46fafa61019c4c110ff",
        "lessThan": "b0aa3e8e2ab4ca92adb28a3ef41873b3363b8676",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "a081c13e39b5c17052a7b46fafa61019c4c110ff",
        "lessThan": "c1dea15f819cded9b3faf58f8bec72323568b6e6",
        "versionType": "git"
      }
    ],
    "programFiles": [
      "drivers/scsi/libiscsi_tcp.c"
    ],
    "defaultStatus": "unaffected"
  },
  {
    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
    "vendor": "Linux",
    "product": "Linux",
    "versions": [
      {
        "status": "affected",
        "version": "2.6.29"
      },
      {
        "status": "unaffected",
        "version": "0",
        "lessThan": "2.6.29",
        "versionType": "semver"
      },
      {
        "status": "unaffected",
        "version": "5.10.265",
        "versionType": "semver",
        "lessThanOrEqual": "5.10.*"
      },
      {
        "status": "unaffected",
        "version": "5.15.216",
        "versionType": "semver",
        "lessThanOrEqual": "5.15.*"
      },
      {
        "status": "unaffected",
        "version": "6.1.183",
        "versionType": "semver",
        "lessThanOrEqual": "6.1.*"
      },
      {
        "status": "unaffected",
        "version": "6.6.151",
        "versionType": "semver",
        "lessThanOrEqual": "6.6.*"
      },
      {
        "status": "unaffected",
        "version": "6.12.103",
        "versionType": "semver",
        "lessThanOrEqual": "6.12.*"
      },
      {
        "status": "unaffected",
        "version": "6.18.44",
        "versionType": "semver",
        "lessThanOrEqual": "6.18.*"
      },
      {
        "status": "unaffected",
        "version": "7.1.8",
        "versionType": "semver",
        "lessThanOrEqual": "7.1.*"
      },
      {
        "status": "unaffected",
        "version": "7.2",
        "versionType": "original_commit_for_fix",
        "lessThanOrEqual": "*"
      }
    ],
    "programFiles": [
      "drivers/scsi/libiscsi_tcp.c"
    ],
    "defaultStatus": "affected"
  }
]
Related CVEs
CVE-2026-74556

Source reference: /cveMetadata/cveId

Publisher severity

critical

Source reference: /containers/cna/metrics

Event
#33204 · Revision 1
Added to Heist Feed
Publisher date
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