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CVE-2026-90189— null_blk: register configfs subsystem after creating default devices

Quick assessment

Affected
Linux Linux
Exploitation
No confirmed in-the-wild exploitation; assess based on exposure
Recommended action
Check the vendor advisory and references for a fixed version. If immediate upgrade is impossible, restrict exposure and increase monitoring.

在 Linux 内核中，以下漏洞已得到修复： null_blk：在创建默认设备之后注册 configfs 子系统 当前在 中， 在 之前执行。因此，当 以模块形式构建时，用户空间中的 与 操作可能发生竞争，导致在 仍为 0 时进入 。随后 会触发 警告（major=0 但 minors≠0），并导致失败： 此外，在错误设备（err_dev）路径中， 上的所有设备会被销毁，但此时 configfs 仍处于注册状态。如果竞争的 + 将某个用户设备添加到列表中， → 会通过 释放该用户设备的 ，但 路径仍可被访问。用户空

AI Predicted 5.5 Difficulty: Hard EPSS 0.17% · P6

Possible ATT&CK Techniques 1 AI

T1190 · Exploit Public-Facing Application

Affected Version Matrix 14

VendorProduct Version RangeStatus
Linux Linux 3bf2bd20734e3e6ffda53719a9c10fb3ee9c5ffa< 2679b11e9256bd70a5ef41783bab6ad6c34a3db1 affected
3bf2bd20734e3e6ffda53719a9c10fb3ee9c5ffa< dbcedbe4819ae21274ea77469e61e46a878b9943 affected
3bf2bd20734e3e6ffda53719a9c10fb3ee9c5ffa< 57debc907aef66319d244009d3370dcd97388d37 affected
3bf2bd20734e3e6ffda53719a9c10fb3ee9c5ffa< d761be1b8f2bbabc41252deb79a426d3f0d4fa10 affected
3bf2bd20734e3e6ffda53719a9c10fb3ee9c5ffa< cab9bf5f68f76cd44e0ec92bd4a60c9b83656a36 affected
3bf2bd20734e3e6ffda53719a9c10fb3ee9c5ffa< c9d293d6bb0575fcb1f3408129453187e2a28a4e affected
4.14 affected
< 4.14 unaffected
… +6 more rows
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I. Basic Information for CVE-2026-90189

Vulnerability Information
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Vulnerability Title
null_blk: register configfs subsystem after creating default devices
Source: CVE Program / CVE List V5
Vulnerability Description
In the Linux kernel, the following vulnerability has been resolved: null_blk: register configfs subsystem after creating default devices In null_init(), configfs_register_subsystem() currently runs before register_blkdev(), so when null_blk is built as a module, a racing mkdir() + poweron from userspace can reach null_add_dev() while null_major is still 0. __add_disk() then hits WARN_ON(disk->minors) (major=0 with minors!=0) and fails: [root@fedora ~]# [ 2366.521436] WARNING: block/genhd.c:476 at __add_disk+0x8a7/0xde0, [ 2366.523552] Modules linked in: null_blk(+) nft_fib_inet nft_fib_ipv4 nft_fib_ipv6 nft_fib [ 2366.529081] CPU: 26 UID: 0 PID: 1600 Comm: sh Not tainted 7.2.0-rc1+ #66 PREEMPT(full) ...... [ 2366.547251] Call Trace: [ 2366.547575] <TASK> [ 2366.547831] ? _raw_spin_lock+0x84/0xe0 [ 2366.548260] add_disk_fwnode+0x114/0x560 [ 2366.548739] null_add_dev+0x102d/0x1b80 [null_blk] [ 2366.549310] ? __pfx_null_add_dev+0x10/0x10 [null_blk] [ 2366.549906] ? mutex_lock+0xde/0x1c0 [ 2366.550361] ? __pfx_mutex_lock+0x10/0x10 [ 2366.550827] nullb_device_power_store+0x1e7/0x280 [null_blk] [ 2366.551499] ? __pfx_nullb_device_power_store+0x10/0x10 [null_blk] [ 2366.552177] ? __kmalloc_cache_noprof+0x1f5/0x470 [ 2366.552748] ? configfs_write_iter+0x35c/0x4e0 [ 2366.553242] configfs_write_iter+0x286/0x4e0 [ 2366.553787] vfs_write+0x52d/0xd00 [ 2366.554169] ? __pfx_vfs_write+0x10/0x10 [ 2366.554679] ? __pfx___css_rstat_updated+0x10/0x10 [ 2366.555196] ? fdget_pos+0x1cf/0x4c0 [ 2366.555649] ksys_write+0xfc/0x1d0 ...... Additionally, the err_dev path destroys all devices on nullb_list while configfs is still registered. If a racing mkdir() + poweron puts a user device on the list, null_destroy_dev()->null_free_dev() kfrees the user device's nullb_device but /sys/kernel/config/nullb/<name> is still reachable. Any userspace access to the item will trigger a UAF. For simplicity, move configfs_register_subsystem() to the end to solve the problems above.
Source: CVE Program / CVE List V5
CVSS Information
N/A
Source: CVE Program / CVE List V5
Vulnerability Type
N/A
Source: CVE Program / CVE List V5

Affected Products

Vendor Product Affected Versions CPE Subscribe
Linux Linux 3bf2bd20734e3e6ffda53719a9c10fb3ee9c5ffa ~ 2679b11e9256bd70a5ef41783bab6ad6c34a3db1 -
Linux Linux 4.14 -

II. Public POCs for CVE-2026-90189

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III. Intelligence Information for CVE-2026-90189

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Patches & Fixes for CVE-2026-90189 (6)

Same Patch Batch · Linux · 2026-09-17 · 600 CVEs total

CVE-2026-90235 9.8 CRITICAL sunrpc: xprtsock: annotate shared socket callbacks with READ_ONCE/WRITE_ONCE
CVE-2026-90104 9.8 CRITICAL NFSv4.1: zero referring call lists before decoding
CVE-2026-90173 9.8 CRITICAL smb: smbdirect: free completion queues with ib_free_cq()
CVE-2026-92489 9.8 CRITICAL xfrm: Fix skb double-free in xfrm_dev_direct_output()
CVE-2026-90151 9.8 CRITICAL NFSv4: remove callback IDR entry on client allocation failure
CVE-2026-90110 9.4 CRITICAL inetpeer: randomize RB-tree node comparison using SipHash
CVE-2026-90230 9.1 CRITICAL nvmet: fix heap out-of-bounds read in nvmet_auth_negotiate()
CVE-2026-90414 9.1 CRITICAL IB/isert: reject PDUs declaring more data than was received
CVE-2026-90413 9.1 CRITICAL IB/isert: reject login PDUs declaring more data than was received
CVE-2026-90380 8.8 HIGH wifi: mt76: mt792x: fix use-after-free in mt76_rx_poll_complete
CVE-2026-93042 8.8 HIGH dmaengine: dw-edma: Terminate all descriptors without callbacks
CVE-2026-90425 8.8 HIGH iommu/tegra241-cmdqv: Require exactly one Stream ID for a vSID
CVE-2026-90240 8.8 HIGH iommu/vt-d: Flush context cache with correct SID when tearing down aliases
CVE-2026-90381 8.8 HIGH wifi: mt76: fix handling channel context with different bands in mt76_switch_vif_chanctx()
CVE-2026-90329 8.8 HIGH HID: synchronize input before cleaning up a failed probe
CVE-2026-90357 8.8 HIGH wifi: mt76: mt7915: unlink TWT flow if the MCU rejects the agreement
CVE-2026-90379 8.8 HIGH wifi: mt76: mt7921: Add PCIe AER handler support to prevent system crash
CVE-2026-90162 8.8 HIGH ksmbd: defer publishing granted locks to prevent UAF/double-free race
CVE-2026-93189 8.8 HIGH HID: core: quiesce input in hid_hw_stop() to prevent use-after-free
CVE-2026-90255 8.8 HIGH Bluetooth: hci_conn: fix the SCO setup context lifetime

Showing top 20 of 600 CVEs. View all on vendor page &rarr; →

IV. Related Vulnerabilities

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