CVE-2026-89968nvmet-tcp: reject unsolicited H2CData PDUs
- 7.5HighCVSS base score
- 0.82%Exploitation in 30 daysEPSS · top 42% of all CVEs
- NoKnown exploitednot in CISA's KEV catalog
- NonePublic exploitsnone known yet
Description
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.
Timeline
ID reserved
By Linux
- 5 days later
· 5 days later
Published
- 33 days later
· 33 days later
Record updated
Changes after publication (a new score, a public exploit, EPSS crossing 1, 10 or 50 %, leaving KEV) are kept since November 2026; earlier ones are not known.
Scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| LinuxCNA (assigner) | 3.1 | High7.5 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H |
| NVDNVD · Received | 3.1 | High7.5 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H |
- EPSS (exploitation in 30 days)
- 0.82% · top 42% of all CVEs (13 Nov 2026)
The list uses the assigner's score when there is one, then CISA's, then NVD's: High 7.5.
Affected products
- affected 872d26a391da92ed8f0c0f5cb5fef428067b7f30 – < 02341ee424fb2eed16b5b8a9d247492e49335c21
- affected 872d26a391da92ed8f0c0f5cb5fef428067b7f30 – < cade124c06f8e738e3a0df285ed2e08953e6bfaa
- affected 872d26a391da92ed8f0c0f5cb5fef428067b7f30 – < 14beef7d4f123fb458fc9844aa74a071871dcca6
- affected 872d26a391da92ed8f0c0f5cb5fef428067b7f30 – < 9fb527103e53fd43a8e802c2eca407869c204f7a
- affected 872d26a391da92ed8f0c0f5cb5fef428067b7f30 – < 2b71f9193e3d3a352920ba367f1a6db345249038
- affected 872d26a391da92ed8f0c0f5cb5fef428067b7f30 – < cf1484d9a75de6809ef331e16f525aaa41b0e16d
- affected 872d26a391da92ed8f0c0f5cb5fef428067b7f30 – < 1cbed7538946c99e585acefd11c9ba3a0bdbae05
- affected 872d26a391da92ed8f0c0f5cb5fef428067b7f30 – < db62b35cbca052860c519cbcabe7650708528738
- affected 5.0
- unaffected < 5.0
- unaffected 5.10.270 – ≤ 5.10.*
- unaffected 5.15.221 – ≤ 5.15.*
- unaffected 6.1.188 – ≤ 6.1.*
- unaffected 6.6.157 – ≤ 6.6.*
- unaffected 6.12.110 – ≤ 6.12.*
- unaffected 6.18.51 – ≤ 6.18.*
- unaffected 7.2.5 – ≤ 7.2.*
- unaffected 7.3 – ≤ *
References
References8
- https://git.kernel.org/stable/c/02341ee424fb2eed16b5b8a9d247492e49335c21 (opens in a new tab)
- https://git.kernel.org/stable/c/cade124c06f8e738e3a0df285ed2e08953e6bfaa (opens in a new tab)
- https://git.kernel.org/stable/c/14beef7d4f123fb458fc9844aa74a071871dcca6 (opens in a new tab)
- https://git.kernel.org/stable/c/9fb527103e53fd43a8e802c2eca407869c204f7a (opens in a new tab)
- https://git.kernel.org/stable/c/2b71f9193e3d3a352920ba367f1a6db345249038 (opens in a new tab)
- https://git.kernel.org/stable/c/cf1484d9a75de6809ef331e16f525aaa41b0e16d (opens in a new tab)
- https://git.kernel.org/stable/c/1cbed7538946c99e585acefd11c9ba3a0bdbae05 (opens in a new tab)
- https://git.kernel.org/stable/c/db62b35cbca052860c519cbcabe7650708528738 (opens in a new tab)
Sources
The same CVE in the primary databases and aggregators, to check against.
- CVE.org record (opens in a new tab)
- CVE List JSON (GitHub) (opens in a new tab)
- NVD (opens in a new tab)
- FIRST EPSS (opens in a new tab)
- EUVD EUVD-2026-80568 (opens in a new tab)
- OSV.dev (opens in a new tab)
- GitHub Advisories (opens in a new tab)
- CIRCL Vulnerability-Lookup (opens in a new tab)
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[](https://cveledger.app/cve/CVE-2026-89968)Record last updated .