nvmet-tcp: reject unsolicited H2CData PDUs

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2026-89968
StatePUBLISHED
AssignerLinux
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-09-16 11:17:07 UTC
Updated2026-09-16 15:18:21 UTC
DescriptionIn the Linux kernel, the following vulnerability has been resolved: nvmet-tcp: reject unsolicited H2CData PDUs nvmet_tcp_handle_h2c_data_pdu() accepts an H2CData PDU after only checking that its TTAG is a valid in-range command index and that the command's data buffers are mapped. It never checks that the target has actually solicited that data by sending an R2T for the command. A remote host can abuse this. It submits a write command that takes the R2T path and, before the target transmits the R2T, sends an H2CData PDU for that command's tag. The data completes the command early, and when the command then fails synchronously (e.g. a length mismatch caught by nvmet_check_transfer_len()), it is completed a second time. Each completion calls nvmet_tcp_queue_response(), so the same command is added to queue->resp_list twice while it is still linked; the second llist_add() makes the node point to itself (lentry->next == lentry). nvmet_tcp_process_resp_list() then walks that self-referential node and adds the command to resp_send_list twice. With CONFIG_DEBUG_LIST this trips the "list_add double add" check (kernel BUG); without it the loop never terminates and the nvmet_tcp workqueue wedges (soft-lockup). It is remotely triggerable and needs no authentication on an allow_any_host subsystem. Track whether an R2T has been transmitted for a command and reject an H2CData PDU that arrives before it. The flag is cleared on command reuse (nvmet_tcp_get_cmd() zeroes cmd->flags) and stays set across the multiple H2CData PDUs of a single solicited transfer.

Risk And Classification

Primary CVSS: v3.1 7.5 HIGH from 416baaa9-dc9f-4396-8d5f-8c081fb06d67

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

VersionSourceTypeScoreSeverityVector
3.1416baaa9-dc9f-4396-8d5f-8c081fb06d67Secondary7.5HIGHCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
3.1CNADECLARED7.5HIGHCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

CVSS v3.1 Breakdown

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

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

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Linux Linux affected 872d26a391da92ed8f0c0f5cb5fef428067b7f30 02341ee424fb2eed16b5b8a9d247492e49335c21 git Not specified
CNA Linux Linux affected 872d26a391da92ed8f0c0f5cb5fef428067b7f30 cade124c06f8e738e3a0df285ed2e08953e6bfaa git Not specified
CNA Linux Linux affected 872d26a391da92ed8f0c0f5cb5fef428067b7f30 14beef7d4f123fb458fc9844aa74a071871dcca6 git Not specified
CNA Linux Linux affected 872d26a391da92ed8f0c0f5cb5fef428067b7f30 9fb527103e53fd43a8e802c2eca407869c204f7a git Not specified
CNA Linux Linux affected 872d26a391da92ed8f0c0f5cb5fef428067b7f30 2b71f9193e3d3a352920ba367f1a6db345249038 git Not specified
CNA Linux Linux affected 872d26a391da92ed8f0c0f5cb5fef428067b7f30 cf1484d9a75de6809ef331e16f525aaa41b0e16d git Not specified
CNA Linux Linux affected 872d26a391da92ed8f0c0f5cb5fef428067b7f30 1cbed7538946c99e585acefd11c9ba3a0bdbae05 git Not specified
CNA Linux Linux affected 872d26a391da92ed8f0c0f5cb5fef428067b7f30 db62b35cbca052860c519cbcabe7650708528738 git Not specified
CNA Linux Linux affected 5.0 Not specified
CNA Linux Linux unaffected 5.0 semver Not specified
CNA Linux Linux unaffected 5.10.270 5.10.* semver Not specified
CNA Linux Linux unaffected 5.15.221 5.15.* semver Not specified
CNA Linux Linux unaffected 6.1.188 6.1.* semver Not specified
CNA Linux Linux unaffected 6.6.157 6.6.* semver Not specified
CNA Linux Linux unaffected 6.12.110 6.12.* semver Not specified
CNA Linux Linux unaffected 6.18.51 6.18.* semver Not specified
CNA Linux Linux unaffected 7.2.5 7.2.* semver Not specified
CNA Linux Linux unaffected 7.3-rc2 * original_commit_for_fix Not specified

References

ReferenceSourceLinkTags
git.kernel.org/stable/c/cf1484d9a75de6809ef331e16f525aaa41b0e16d 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/14beef7d4f123fb458fc9844aa74a071871dcca6 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/9fb527103e53fd43a8e802c2eca407869c204f7a 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/02341ee424fb2eed16b5b8a9d247492e49335c21 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/db62b35cbca052860c519cbcabe7650708528738 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/2b71f9193e3d3a352920ba367f1a6db345249038 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/cade124c06f8e738e3a0df285ed2e08953e6bfaa 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/1cbed7538946c99e585acefd11c9ba3a0bdbae05 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
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