{
  "threat_severity" : "Important",
  "public_date" : "2026-08-15T00:00:00Z",
  "bugzilla" : {
    "description" : "kernel: scsi: libiscsi_tcp: Bound SCSI Response data segment to the connection buffer",
    "id" : "2517010",
    "url" : "https://bugzilla.redhat.com/show_bug.cgi?id=2517010"
  },
  "cvss3" : {
    "cvss3_base_score" : "7.2",
    "cvss3_scoring_vector" : "CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H",
    "status" : "draft"
  },
  "cwe" : "CWE-120",
  "details" : [ "In the Linux kernel, the following vulnerability has been resolved:\nscsi: libiscsi_tcp: Bound SCSI Response data segment to the connection buffer\niscsi_tcp_hdr_dissect() receives the data segment of several PDU types\ninto the fixed-size conn->data 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.\nThe SCSI Command Response (ISCSI_OP_SCSI_CMD_RSP) path also copies its\ndata segment (sense/response data) into conn->data via\niscsi_tcp_data_recv_prep(), but it does so without the same check.  The\nonly upstream bound on in.datalen is conn->max_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->data buffer.\nOnce the same bound applies, ISCSI_OP_SCSI_CMD_RSP is handled exactly\nlike those responses: bound the data segment, receive it into conn->data\nwhen present, and otherwise complete the PDU with no data.  Fold the\nopcode into that case group rather than duplicating the check.", "A flaw was found in the Linux kernel's `libiscsi_tcp` component. A remote attacker, acting as a malicious iSCSI target, could send a specially crafted iSCSI SCSI Command Response (ISCSI_OP_SCSI_CMD_RSP) with an oversized data segment. This could lead to a buffer overflow in a fixed-size buffer, potentially causing memory corruption within the kernel." ],
  "package_state" : [ {
    "product_name" : "Red Hat Enterprise Linux 10",
    "fix_state" : "Affected",
    "package_name" : "kernel",
    "cpe" : "cpe:/o:redhat:enterprise_linux:10"
  }, {
    "product_name" : "Red Hat Enterprise Linux 6",
    "fix_state" : "Not affected",
    "package_name" : "kernel",
    "cpe" : "cpe:/o:redhat:enterprise_linux:6"
  }, {
    "product_name" : "Red Hat Enterprise Linux 7",
    "fix_state" : "Affected",
    "package_name" : "kernel",
    "cpe" : "cpe:/o:redhat:enterprise_linux:7"
  }, {
    "product_name" : "Red Hat Enterprise Linux 7",
    "fix_state" : "Affected",
    "package_name" : "kernel-rt",
    "cpe" : "cpe:/o:redhat:enterprise_linux:7"
  }, {
    "product_name" : "Red Hat Enterprise Linux 8",
    "fix_state" : "Affected",
    "package_name" : "kernel",
    "cpe" : "cpe:/o:redhat:enterprise_linux:8"
  }, {
    "product_name" : "Red Hat Enterprise Linux 8",
    "fix_state" : "Affected",
    "package_name" : "kernel-rt",
    "cpe" : "cpe:/o:redhat:enterprise_linux:8"
  }, {
    "product_name" : "Red Hat Enterprise Linux 9",
    "fix_state" : "Affected",
    "package_name" : "kernel",
    "cpe" : "cpe:/o:redhat:enterprise_linux:9"
  }, {
    "product_name" : "Red Hat Enterprise Linux 9",
    "fix_state" : "Affected",
    "package_name" : "kernel-rt",
    "cpe" : "cpe:/o:redhat:enterprise_linux:9"
  } ],
  "references" : [ "https://www.cve.org/CVERecord?id=CVE-2026-74556\nhttps://nvd.nist.gov/vuln/detail/CVE-2026-74556\nhttps://lore.kernel.org/linux-cve-announce/2026081551-CVE-2026-74556-3eb4@gregkh/T" ],
  "name" : "CVE-2026-74556",
  "mitigation" : {
    "value" : "If iSCSI initiator functionality is not required, prevent the `libiscsi_tcp` kernel module from loading by blacklisting it. Create a file such as `/etc/modprobe.d/blacklist-iscsi.conf` with the content `blacklist libiscsi_tcp`. A system reboot is required for this change to take effect. This may impact systems relying on iSCSI storage.",
    "lang" : "en:us"
  },
  "csaw" : false
}