Vulnerability in Linux kernel (CVE-2026-89968)
Summary
Vulnerability in Linux kernel (CVE-2026-89968). Risk of unauthorized operations or information disclosure.
Original description
The description as published by the source.
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 s…
Source: NIST National Vulnerability Database NVD GitHub Advisory
Auto-generated summary
Assembled by SecPulse from the source data (CVSS, CWE, affected versions) using templates — no AI involved. Check the original description and references below for exact details.
A vulnerability tracked as CVE-2026-89968 has been found in Linux kernel.
Risk of unauthorized operations or information disclosure. CVSS score: 7.5/10.
What to do: apply the vendor's official patched release.
If unsure, ask your IT team or search "Linux kernel CVE-2026-89968" on the vendor's site.
CVE-2026-89968 (Linux kernel) — CVSS v3 7.5
Attack vector: remote (network-reachable) / unauthenticated / no user interaction
Plan: 1) Audit SBOM/dependencies, 2) Stage→prod upgrade, 3) Add WAF/proxy monitoring on affected endpoints, 4) Hunt IOCs in logs.
Refs: see the GHSA / vendor advisory / patched release linked on this page.
A vulnerability (unclassified) exists in Linux kernel.
Check the vendor advisory for the affected versions of Linux kernel.
Severity: High (CVSS 7.5/10). Risk of unauthorized operations or information disclosure.
Update to the patched release per vendor advisory.
Until the patch is applied: disable the affected feature, apply WAF rules, or restrict access via network ACLs.
Search webserver/proxy logs for unusual request patterns matching this CVE's known IOCs. Audit SBOM/dependencies to find affected services.
Response actions
Concrete steps and command examples for SOC/SRE teams to execute in order
-
1Identify exposure identify
Audit SBOM/dependencies for affected components.資産台帳・SBOM・依存マニフェストで Linux kernel を使っているサービスとバージョンを洗い出す。
-
2Post-deployment verification verify
Confirm patched version is live in productionパッチ適用後、ステージングで PoC または同等の悪用パターンを再現して脆弱性が閉じたことを確認。本番ではアクセスログ・WAF でアラート再発が無いか継続監視。
References
- web git.kernel.org
- web git.kernel.org
- web git.kernel.org
- web git.kernel.org
- web git.kernel.org
- web git.kernel.org
- web git.kernel.org
- web git.kernel.org
- web nvd.nist.gov
- web github.com