scsi: libiscsi_tcp: Bound SCSI Response data segment to the connection buffer

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2026-74556
StatePUBLISHED
AssignerLinux
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-08-15 13:18:01 UTC
Updated2026-08-17 06:19:53 UTC
DescriptionIn 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.

Risk And Classification

Primary CVSS: v3.1 9.8 CRITICAL from 416baaa9-dc9f-4396-8d5f-8c081fb06d67

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

EPSS: 0.001570000 probability, percentile 0.053400000 (date 2026-08-16)

VersionSourceTypeScoreSeverityVector
3.1416baaa9-dc9f-4396-8d5f-8c081fb06d67Secondary9.8CRITICALCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
3.1CNADECLARED9.8CRITICALCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

CVSS v3.1 Breakdown

Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Linux Linux affected a081c13e39b5c17052a7b46fafa61019c4c110ff c97b5265cc47775f77fd2a23d6bde0426997b233 git Not specified
CNA Linux Linux affected a081c13e39b5c17052a7b46fafa61019c4c110ff 084af0253673425ce2ae62e3c7f74f0dd023711b git Not specified
CNA Linux Linux affected a081c13e39b5c17052a7b46fafa61019c4c110ff 72815741715bd41556dac5eeb068bf0f8af06ee7 git Not specified
CNA Linux Linux affected a081c13e39b5c17052a7b46fafa61019c4c110ff b0aa3e8e2ab4ca92adb28a3ef41873b3363b8676 git Not specified
CNA Linux Linux affected a081c13e39b5c17052a7b46fafa61019c4c110ff c1dea15f819cded9b3faf58f8bec72323568b6e6 git Not specified
CNA Linux Linux affected 2.6.29 Not specified
CNA Linux Linux unaffected 2.6.29 semver Not specified
CNA Linux Linux unaffected 6.6.151 6.6.* semver Not specified
CNA Linux Linux unaffected 6.12.103 6.12.* semver Not specified
CNA Linux Linux unaffected 6.18.44 6.18.* semver Not specified
CNA Linux Linux unaffected 7.1.8 7.1.* semver Not specified
CNA Linux Linux unaffected 7.2 * original_commit_for_fix Not specified

References

ReferenceSourceLinkTags
git.kernel.org/stable/c/c1dea15f819cded9b3faf58f8bec72323568b6e6 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/b0aa3e8e2ab4ca92adb28a3ef41873b3363b8676 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/084af0253673425ce2ae62e3c7f74f0dd023711b 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/72815741715bd41556dac5eeb068bf0f8af06ee7 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/c97b5265cc47775f77fd2a23d6bde0426997b233 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
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