{
  "affected": [
    {
      "ranges": [
        {
          "events": [
            {
              "introduced": "a081c13e39b5c17052a7b46fafa61019c4c110ff"
            },
            {
              "fixed": "c97b5265cc47775f77fd2a23d6bde0426997b233"
            },
            {
              "fixed": "084af0253673425ce2ae62e3c7f74f0dd023711b"
            },
            {
              "fixed": "72815741715bd41556dac5eeb068bf0f8af06ee7"
            },
            {
              "fixed": "b0aa3e8e2ab4ca92adb28a3ef41873b3363b8676"
            },
            {
              "fixed": "c1dea15f819cded9b3faf58f8bec72323568b6e6"
            }
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "type": "GIT"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "Linux",
        "name": "Kernel"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "2.6.29"
            },
            {
              "fixed": "6.6.151"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "6.7.0"
            },
            {
              "fixed": "6.12.103"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "6.13.0"
            },
            {
              "fixed": "6.18.44"
            }
          ],
          "type": "ECOSYSTEM"
        },
        {
          "events": [
            {
              "introduced": "6.19.0"
            },
            {
              "fixed": "7.1.8"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "database_specific": {
    "cna_assigner": "Linux",
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/74xxx/CVE-2026-74556.json"
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nscsi: libiscsi_tcp: Bound SCSI Response data segment to the connection buffer\n\niscsi_tcp_hdr_dissect() receives the data segment of several PDU types\ninto the fixed-size conn-\u003edata buffer, which is allocated for\nISCSI_DEF_MAX_RECV_SEG_LEN (8192) bytes.  For the LOGIN_RSP, TEXT_RSP,\nREJECT and ASYNC_EVENT opcodes the dissect path already rejects a PDU\nwhose DataSegmentLength exceeds that buffer.\n\nThe SCSI Command Response (ISCSI_OP_SCSI_CMD_RSP) path also copies its\ndata segment (sense/response data) into conn-\u003edata via\niscsi_tcp_data_recv_prep(), but it does so without the same check.  The\nonly upstream bound on in.datalen is conn-\u003emax_recv_dlength, the\ninitiator's advertised MaxRecvDataSegmentLength, which is commonly\nnegotiated well above 8192 (open-iscsi defaults to 262144).  A target\nthat returns a SCSI Response with a DataSegmentLength between 8193 and\nmax_recv_dlength therefore overflows the 8192-byte conn-\u003edata buffer.\n\nOnce the same bound applies, ISCSI_OP_SCSI_CMD_RSP is handled exactly\nlike those responses: bound the data segment, receive it into conn-\u003edata\nwhen present, and otherwise complete the PDU with no data.  Fold the\nopcode into that case group rather than duplicating the check.",
  "id": "CVE-2026-74556",
  "modified": "2026-08-18T03:30:51.238166330Z",
  "published": "2026-08-15T12:28:01.359Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/084af0253673425ce2ae62e3c7f74f0dd023711b"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/72815741715bd41556dac5eeb068bf0f8af06ee7"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/b0aa3e8e2ab4ca92adb28a3ef41873b3363b8676"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/c1dea15f819cded9b3faf58f8bec72323568b6e6"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/c97b5265cc47775f77fd2a23d6bde0426997b233"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/74xxx/CVE-2026-74556.json"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-74556"
    },
    {
      "type": "PACKAGE",
      "url": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"
    }
  ],
  "schema_version": "1.9.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
      "type": "CVSS_V3"
    }
  ],
  "summary": "scsi: libiscsi_tcp: Bound SCSI Response data segment to the connection buffer"
}