{"id":"CVE-2026-90190","title":"In the Linux kernel, the following vulnerability has been resolved:\n\nnull_blk: use DEFINE_MUTEX for the file-scope mutex\n\nIn null_init(), mutex_init(&lock) currently happens after\nconfigfs_register_subsystem(), which exposes the nullb su…","summary":"In the Linux kernel, the following vulnerability has been resolved:\n\nnull_blk: use DEFINE_MUTEX for the file-scope mutex\n\nIn null_init(), mutex_init(&lock) currently happens after\nconfigfs_register_subsystem(), which exposes the nullb su…","severity":"none","vendor":"Linux","product":"Linux","affected":["Linux >= 49c3b9266a718dbd73c42e004288b4bb2ea0ac0b < f9f4ca45c770b7eec83fea6c9b727b26e691b513","Linux >= 49c3b9266a718dbd73c42e004288b4bb2ea0ac0b < 349903f7ee72f7ac5b7a98840d701b2082d140a3","Linux >= 49c3b9266a718dbd73c42e004288b4bb2ea0ac0b < 0a8c2f7b95981913ac370683e34db4906970c210","Linux >= 49c3b9266a718dbd73c42e004288b4bb2ea0ac0b < c7dea90c9b4ef1dfbd2e4df36de180c76fd7c33c","Linux >= 49c3b9266a718dbd73c42e004288b4bb2ea0ac0b < 234117949da3b3f9705a21b66094f9f30bbe681d","Linux >= 49c3b9266a718dbd73c42e004288b4bb2ea0ac0b < 017dac7670909eaea3eb36e6b3b5a8be9ce0a14d","Linux 5.19"],"published":"2026-09-17","updated":"2026-09-17","sourceUpdated":"2026-09-17T17:17:13.670","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-90190","references":[{"url":"https://git.kernel.org/stable/c/017dac7670909eaea3eb36e6b3b5a8be9ce0a14d","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/0a8c2f7b95981913ac370683e34db4906970c210","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/234117949da3b3f9705a21b66094f9f30bbe681d","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/349903f7ee72f7ac5b7a98840d701b2082d140a3","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/c7dea90c9b4ef1dfbd2e4df36de180c76fd7c33c","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/f9f4ca45c770b7eec83fea6c9b727b26e691b513","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"}],"tags":["nvd","cve.org"],"ingestedAt":"2026-09-17T16:21:47.864Z","epss":0.00205,"epssPercentile":0.10899,"slug":"CVE-2026-90190","body":"## Overview\n\nIn the Linux kernel, the following vulnerability has been resolved:\n\nnull_blk: use DEFINE_MUTEX for the file-scope mutex\n\nIn null_init(), mutex_init(&lock) currently happens after\nconfigfs_register_subsystem(), which exposes the nullb subsystem to\nuserspace. A racing mkdir() into /sys/kernel/config/nullb/ can reach\nnull_find_dev_by_name() -> mutex_lock(&lock) before the mutex is\ninitialized, trigger warning:\n\n[  123.137788] DEBUG_LOCKS_WARN_ON(lock->magic != lock)\n[  123.137796] WARNING: kernel/locking/mutex.c:159 at mutex_lock+0x171/0x1c0, CPU#13: mkdir/1301\n[  123.140090] Modules linked in: null_blk(+) nft_fib_inet nft_fib_ipv4\n......\n[  123.154926] Call Trace:\n[  123.155172]  <TASK>\n[  123.155419]  ? __pfx_mutex_lock+0x10/0x10\n[  123.156181]  ? __pfx__raw_spin_lock+0x10/0x10\n[  123.156571]  nullb_group_make_group+0x20/0x100 [null_blk]\n[  123.157011]  configfs_mkdir+0x47b/0xc70\n[  123.157337]  ? __pfx_configfs_mkdir+0x10/0x10\n[  123.157719]  ? may_create_dentry+0x242/0x2e0\n[  123.158061]  vfs_mkdir+0x2a9/0x6c0\n[  123.158352]  filename_mkdirat+0x3dc/0x500\n[  123.158710]  ? __pfx_filename_mkdirat+0x10/0x10\n[  123.159070]  ? strncpy_from_user+0x3a/0x1d0\n[  123.159413]  __x64_sys_mkdir+0x6b/0x90\n[  123.159760]  do_syscall_64+0xea/0x600\n\nReplace the runtime mutex_init(&lock) with a static DEFINE_MUTEX(lock)\ndeclaration to fix this issue.\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.","depth":"sunlit","depthScore":3,"depthScoreParts":{"impact":2.8,"likelihood":0,"exploitation":0,"ransomware":0},"changes":[]}