{"id":"CVE-2026-90189","revision":"879c4323c3774ed6b04910ed8e03254f","records":[{"revision":"879c4323c3774ed6b04910ed8e03254f","observedAt":"2026-10-23T15:48:27.903+00:00","statement":{"source":"cve-program","id":"CVE-2026-90189","aliases":[],"title":"null_blk: register configfs subsystem after creating default devices","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nnull_blk: register configfs subsystem after creating default devices\n\nIn null_init(), configfs_register_subsystem() currently runs before\nregister_blkdev(), so when null_blk is built as a module, a racing mkdir()\n+ poweron from userspace can reach null_add_dev() while null_major is still\n0. __add_disk() then hits WARN_ON(disk->minors) (major=0 with minors!=0)\nand fails:\n\n[root@fedora ~]# [ 2366.521436] WARNING: block/genhd.c:476 at __add_disk+0x8a7/0xde0,\n[ 2366.523552] Modules linked in: null_blk(+) nft_fib_inet nft_fib_ipv4 nft_fib_ipv6 nft_fib\n[ 2366.529081] CPU: 26 UID: 0 PID: 1600 Comm: sh Not tainted 7.2.0-rc1+ #66 PREEMPT(full)\n......\n[ 2366.547251] Call Trace:\n[ 2366.547575] \n[ 2366.547831] ? _raw_spin_lock+0x84/0xe0\n[ 2366.548260] add_disk_fwnode+0x114/0x560\n[ 2366.548739] null_add_dev+0x102d/0x1b80 [null_blk]\n[ 2366.549310] ? __pfx_null_add_dev+0x10/0x10 [null_blk]\n[ 2366.549906] ? mutex_lock+0xde/0x1c0\n[ 2366.550361] ? __pfx_mutex_lock+0x10/0x10\n[ 2366.550827] nullb_device_power_store+0x1e7/0x280 [null_blk]\n[ 2366.551499] ? __pfx_nullb_device_power_store+0x10/0x10 [null_blk]\n[ 2366.552177] ? __kmalloc_cache_noprof+0x1f5/0x470\n[ 2366.552748] ? configfs_write_iter+0x35c/0x4e0\n[ 2366.553242] configfs_write_iter+0x286/0x4e0\n[ 2366.553787] vfs_write+0x52d/0xd00\n[ 2366.554169] ? __pfx_vfs_write+0x10/0x10\n[ 2366.554679] ? __pfx___css_rstat_updated+0x10/0x10\n[ 2366.555196] ? fdget_pos+0x1cf/0x4c0\n[ 2366.555649] ksys_write+0xfc/0x1d0\n......\n\nAdditionally, the err_dev path destroys all devices on nullb_list while\nconfigfs is still registered. If a racing mkdir() + poweron puts a user\ndevice on the list, null_destroy_dev()->null_free_dev() kfrees the user\ndevice's nullb_device but /sys/kernel/config/nullb/ is still\nreachable. Any userspace access to the item will trigger a UAF.\n\nFor simplicity, move configfs_register_subsystem() to the end to solve\nthe problems above.","state":0,"publishedAt":"2026-09-17T16:07:10.992+00:00","modifiedAt":"2026-10-19T08:59:25.945+00:00","affected":[{"ecosystem":"Vendor product","name":"Linux","ranges":[],"versions":[],"rawVersionEvidence":"{\n \"product\": \"Linux\",\n \"vendor\": \"Linux\",\n \"defaultStatus\": \"unaffected\",\n \"repo\": \"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\n \"programFiles\": [\n \"drivers/block/null_blk/main.c\"\n ],\n \"versions\": [\n {\n \"version\": \"3bf2bd20734e3e6ffda53719a9c10fb3ee9c5ffa\",\n \"lessThan\": \"2679b11e9256bd70a5ef41783bab6ad6c34a3db1\",\n \"status\": \"affected\",\n \"versionType\": \"git\"\n },\n {\n \"version\": \"3bf2bd20734e3e6ffda53719a9c10fb3ee9c5ffa\",\n \"lessThan\": \"dbcedbe4819ae21274ea77469e61e46a878b9943\",\n \"status\": \"affected\",\n \"versionType\": \"git\"\n },\n {\n \"version\": \"3bf2bd20734e3e6ffda53719a9c10fb3ee9c5ffa\",\n \"lessThan\": \"57debc907aef66319d244009d3370dcd97388d37\",\n \"status\": \"affected\",\n \"versionType\": \"git\"\n },\n {\n \"version\": \"3bf2bd20734e3e6ffda53719a9c10fb3ee9c5ffa\",\n \"lessThan\": \"d761be1b8f2bbabc41252deb79a426d3f0d4fa10\",\n \"status\": \"affected\",\n \"versionType\": \"git\"\n },\n {\n \"version\": \"3bf2bd20734e3e6ffda53719a9c10fb3ee9c5ffa\",\n \"lessThan\": \"cab9bf5f68f76cd44e0ec92bd4a60c9b83656a36\",\n \"status\": \"affected\",\n \"versionType\": \"git\"\n },\n {\n \"version\": \"3bf2bd20734e3e6ffda53719a9c10fb3ee9c5ffa\",\n \"lessThan\": \"c9d293d6bb0575fcb1f3408129453187e2a28a4e\",\n \"status\": \"affected\",\n \"versionType\": \"git\"\n }\n ]\n }"},{"ecosystem":"Vendor product","name":"Linux","ranges":[],"versions":[],"rawVersionEvidence":"{\n \"product\": \"Linux\",\n \"vendor\": \"Linux\",\n \"defaultStatus\": \"affected\",\n \"repo\": \"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\n \"programFiles\": [\n \"drivers/block/null_blk/main.c\"\n ],\n \"versions\": [\n {\n \"version\": \"4.14\",\n \"status\": \"affected\"\n },\n {\n \"version\": \"0\",\n \"lessThan\": \"4.14\",\n \"status\": \"unaffected\",\n \"versionType\": \"semver\"\n },\n {\n \"version\": \"6.1.188\",\n \"lessThanOrEqual\": \"6.1.*\",\n \"status\": \"unaffected\",\n \"versionType\": \"semver\"\n },\n {\n \"version\": \"6.6.157\",\n \"lessThanOrEqual\": \"6.6.*\",\n \"status\": \"unaffected\",\n \"versionType\": \"semver\"\n },\n {\n \"version\": \"6.12.110\",\n \"lessThanOrEqual\": \"6.12.*\",\n \"status\": \"unaffected\",\n \"versionType\": \"semver\"\n },\n {\n \"version\": \"6.18.52\",\n \"lessThanOrEqual\": \"6.18.*\",\n \"status\": \"unaffected\",\n \"versionType\": \"semver\"\n },\n {\n \"version\": \"7.2.6\",\n \"lessThanOrEqual\": \"7.2.*\",\n \"status\": \"unaffected\",\n \"versionType\": \"semver\"\n },\n {\n \"version\": \"7.3\",\n \"lessThanOrEqual\": \"*\",\n \"status\": \"unaffected\",\n \"versionType\": \"original_commit_for_fix\"\n }\n ]\n }"}],"metrics":[],"references":["https://git.kernel.org/stable/c/2679b11e9256bd70a5ef41783bab6ad6c34a3db1","https://git.kernel.org/stable/c/dbcedbe4819ae21274ea77469e61e46a878b9943","https://git.kernel.org/stable/c/57debc907aef66319d244009d3370dcd97388d37","https://git.kernel.org/stable/c/d761be1b8f2bbabc41252deb79a426d3f0d4fa10","https://git.kernel.org/stable/c/cab9bf5f68f76cd44e0ec92bd4a60c9b83656a36","https://git.kernel.org/stable/c/c9d293d6bb0575fcb1f3408129453187e2a28a4e"],"sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-90189","license":"CVE Program Terms of Use","key":"cve-program:CVE-2026-90189","identifiers":["CVE-2026-90189"]},"retained":false,"historicalAffected":[]}],"coverage":[]}