Vulnerability in Kernel (CVE-2026-43054)

Summary

Vulnerability in Kernel (CVE-2026-43054). Risk of unauthorized operations or information disclosure. Mitigation: upgrade to 5.15.203, 6.1.168, 6.6.134, 6.12.81, 6.18.22, 6.19.12 or later.

Original description

The description as published by the source.

In the Linux kernel, the following vulnerability has been resolved:

scsi: target: tcm_loop: Drain commands in target_reset handler

tcm_loop_target_reset() violates the SCSI EH contract: it returns SUCCESS
without draining any in-flight commands. The SCSI EH documentation
(scsi_eh.rst) requires that when a reset handler returns SUCCESS the driver
has made lower layers "forget about timed out scmds" and is ready for new
commands. Every other SCSI LLD (virtio_scsi, mpt3sas, ipr, scsi_debug,
mpi3mr) enforces this by draining or completing outstanding commands before
returning SUCCESS.

Because tcm_loop_target_reset() doesn't drain, the SCSI EH reuses in-flight
scsi_cmnd structures for recovery commands (e.g. TUR) while the target core
still has async completion work queued for the old se_cmd. The memset in
queuecommand zeroes se_lun and lun_ref_active, causing
transport_lun_remove_cmd() to skip its percpu_ref_put(). The leaked LUN
reference prevents transport_clear_lun_ref() from completing, hanging
configfs LUN unlink forever in D-state:

INFO: task rm:264 blocked for more than 122 seconds.
rm D 0 264 258 0x00004000
Call Trace:
__schedule+0x3d0/0x8e0
schedule+0x36/0xf0
transport_clear_lun_ref+0x78/0x90 [target_core_mod]
core_tpg_remove_lun+0x28/0xb0 [target_core_mod]
target_fabric_port_unlink+0x50/0x60 [target_core_mod]
configfs_unlink+0x156/0x1f0 [configfs]
vfs_unlink+0x109/0x290
do_unlinkat+0x1d5/0x2d0

Fix this by makin…

Source: OSV.dev (Open Source Vulnerabilities) NVD OSV

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-2026-43054 has been found in Kernel.
Risk of unauthorized operations or information disclosure.
What to do: upgrade Kernel to 5.15.203, 6.1.168, 6.6.134, 6.12.81, 6.18.22, 6.19.12 or later.
If unsure, ask your IT team or search "Kernel CVE-2026-43054" on the vendor's site.

CVE-2026-43054 (Kernel)
Patched: 5.15.203, 6.1.168, 6.6.134, 6.12.81, 6.18.22, 6.19.12 — apply immediately
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.

❓ What is the problem

A vulnerability (unclassified) exists in Kernel.

📍 Affected scope

Check the vendor advisory for the affected versions of Kernel.

🔥 Severity

Severity: ?. Risk of unauthorized operations or information disclosure.

🔧 How to fix

Update to 5.15.203, 6.1.168, 6.6.134, 6.12.81, 6.18.22, 6.19.12.

🛡️ Workaround

Until the patch is applied: disable the affected feature, apply WAF rules, or restrict access via network ACLs.

🔍 Detection

Search webserver/proxy logs for unusual request patterns matching this CVE's known IOCs. Run grep -r 'Kernel' . against your dependency files (package-lock.json, requirements.txt, go.sum) to find affected services.

Response actions

Concrete steps and command examples for SOC/SRE teams to execute in order

1
Identify exposure identify
```
grep -r 'Kernel' . | grep -v node_modules
```
リポジトリと本番環境の依存ファイル (package-lock.json / requirements.txt / go.sum / Gemfile.lock 等) で Kernel を grep し、稼働しているサービス・バージョンを把握する。
2
Apply patch patch
```
Upgrade Kernel to 5.15.203, 6.1.168, 6.6.134, 6.12.81, 6.18.22, 6.19.12
```
ステージング環境で 5.15.203, 6.1.168, 6.6.134, 6.12.81, 6.18.22, 6.19.12 に上げて回帰テスト → 本番反映。回帰テストはアプリの主要ハッピーパスを含めること。
3
Post-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。

Affected packages

Linux Kernel

[{"type":"ECOSYSTEM","events":[{"introduced":"5.13.0"},{"fixed":"5.15.203"}]},{"type":"ECOSYSTEM","events":[{"introduced":"5.16.0"},{"fixed":"6.1.168"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.2.0"},{"fixed":"6.6.134"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.7.0"},{"fixed":"6.12.81"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.13.0"},{"fixed":"6.18.22"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.19.0"},{"fixed":"6.19.12"}]}]

Fix status by distribution

Fixed packages published by each distribution for this CVE

BellSoft Alpaquita BELL-CVE-2026-43054 linux-lts Fixed in: 6.1.168-r0
Debian DEBIAN-CVE-2026-43054 linux Fixed in: 6.1.170-1
Ubuntu UBUNTU-CVE-2026-43054 linux-hwe-edge