Answer in brief
CVE-2026-89968 records a High severity (CVSS 7.5) vulnerability in nvmet-tcp: reject unsolicited H2CData PDUs. The current sources do not mark it as known exploited. The current feed maps Linux/Linux (generic), Linux/Linux (generic). Check affected ranges and fixed versions before updating.
Analysis pending evidence review
HOL Guard separates source facts from reviewed analysis. See the methodology.
CVSS is 7.5. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.
Analysis status
Analysis pending evidence review
Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.
The current feed maps Linux/Linux (generic), Linux/Linux (generic). Check affected ranges and fixed versions before updating.
| Package | Affected range | Fixed version |
|---|---|---|
| Linux/Linuxgeneric | >=872d26a391da92ed8f0c0f5cb5fef428067b7f30 <02341ee424fb2eed16b5b8a9d247492e49335c21 || >=872d26a391da92ed8f0c0f5cb5fef428067b7f30 <cade124c06f8e738e3a0df285ed2e08953e6bfaa || >=872d26a391da92ed8f0c0f5cb5fef428067b7f30 <14beef7d4f123fb458fc9844aa74a071871dcca6 || >=872d26a391da92ed8f0c0f5cb5fef428067b7f30 <9fb527103e53fd43a8e802c2eca407869c204f7a || >=872d26a391da92ed8f0c0f5cb5fef428067b7f30 <2b71f9193e3d3a352920ba367f1a6db345249038 || >=872d26a391da92ed8f0c0f5cb5fef428067b7f30 <cf1484d9a75de6809ef331e16f525aaa41b0e16d || >=872d26a391da92ed8f0c0f5cb5fef428067b7f30 <1cbed7538946c99e585acefd11c9ba3a0bdbae05 || >=872d26a391da92ed8f0c0f5cb5fef428067b7f30 <db62b35cbca052860c519cbcabe7650708528738 | 02341ee424fb2eed16b5b8a9d247492e49335c21, cade124c06f8e738e3a0df285ed2e08953e6bfaa, 14beef7d4f123fb458fc9844aa74a071871dcca6, 9fb527103e53fd43a8e802c2eca407869c204f7a, 2b71f9193e3d3a352920ba367f1a6db345249038, cf1484d9a75de6809ef331e16f525aaa41b0e16d, 1cbed7538946c99e585acefd11c9ba3a0bdbae05, db62b35cbca052860c519cbcabe7650708528738 |
| Linux/Linuxgeneric | 5.0 | Not reported |
Published upstream
Sep 16, 2026
Evidence: source:cvelist:source_dates:source-dates:recordSource modified
Oct 19, 2026
Evidence: source:cvelist:source_dates:source-dates:recordFirst seen by HOL
Sep 16, 2026
In 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.
Quoted source text, attributed separately from HOL analysis.