CVE-2026-74556

Technical Description

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

Remediation

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

References