scsi: libiscsi_tcp: Bound SCSI Response data segment to the connection buffer
Collected exploitation and prediction evidence
Risk source coverageCISA KEV is observed exploitation evidence. FIRST EPSS is a dated prediction of exploitation in the next 30 days. Missing scores are unknown. This collector requests predictions only for explicit CVE aliases in the public NuGet archive; Microsoft release views retain their existing prediction scope.
No collected risk observation for these identifiers. This does not establish absence of exploitation or a zero probability.
cve-program · CVE-2026-74556
PublishedIn 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.
- Source published
- 15 Aug 2026 12:28:01 UTC
- Source modified
- 16 Oct 2026 19:05:55 UTC
- Observed here
- 23 Oct 2026 15:48:27 UTC
- Source terms
- CVE Program Terms of Use
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CVSS 3.1 · 9.8 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H