CVE-2026-74556

Status: UPDATED  |  Advisory ID: CVE-2026-74556

Key Details

Affected Products, Subsystems & Sectors

What to Know

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. (NVD)

What to Do

Monitor Linux's web page for any future patch releases.

References