CVE-2026-74556

CVE Details

Release Date:2026-08-15
Impact:Important What is this?

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 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.

See more information about CVE-2026-74556 from MITRE CVE dictionary and NIST NVD


NOTE: The following CVSS metrics and score provided are preliminary and subject to review.


CVSS v3 metrics

Base Score: 7.0
Vector String: CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H
Version: 3.1
Attack Vector: Local
Attack Complexity: High
Privileges Required: Low
User Interaction: None
Scope: Unchanged
Confidentiality Impact: High
Integrity Impact: High
Availability Impact: High

Errata information


PlatformErrataRelease Date
Oracle Linux version 10 (kernel-uek) ELSA-2026-5002482026-09-04
Oracle Linux version 8 (kernel-uek) ELSA-2026-5002492026-09-04
Oracle Linux version 9 (kernel-uek) ELSA-2026-5002482026-09-04
Oracle Linux version 9 (kernel-uek) ELSA-2026-5002492026-09-04


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