Answer in brief
CVE-2026-90189 records a Unknown severity vulnerability in null_blk: register configfs subsystem after creating default devices. 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.
A CVSS score is not reported in the current record. 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 | >=3bf2bd20734e3e6ffda53719a9c10fb3ee9c5ffa <2679b11e9256bd70a5ef41783bab6ad6c34a3db1 || >=3bf2bd20734e3e6ffda53719a9c10fb3ee9c5ffa <dbcedbe4819ae21274ea77469e61e46a878b9943 || >=3bf2bd20734e3e6ffda53719a9c10fb3ee9c5ffa <57debc907aef66319d244009d3370dcd97388d37 || >=3bf2bd20734e3e6ffda53719a9c10fb3ee9c5ffa <d761be1b8f2bbabc41252deb79a426d3f0d4fa10 || >=3bf2bd20734e3e6ffda53719a9c10fb3ee9c5ffa <cab9bf5f68f76cd44e0ec92bd4a60c9b83656a36 || >=3bf2bd20734e3e6ffda53719a9c10fb3ee9c5ffa <c9d293d6bb0575fcb1f3408129453187e2a28a4e | 2679b11e9256bd70a5ef41783bab6ad6c34a3db1, dbcedbe4819ae21274ea77469e61e46a878b9943, 57debc907aef66319d244009d3370dcd97388d37, d761be1b8f2bbabc41252deb79a426d3f0d4fa10, cab9bf5f68f76cd44e0ec92bd4a60c9b83656a36, c9d293d6bb0575fcb1f3408129453187e2a28a4e |
| Linux/Linuxgeneric | 4.14 | Not reported |
Published upstream
Sep 17, 2026
Evidence: source:cvelist:source_dates:source-dates:recordSource modified
Sep 17, 2026
Evidence: source:cvelist:source_dates:source-dates:recordFirst seen by HOL
Sep 17, 2026
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.
Quoted source text, attributed separately from HOL analysis.