{"cve":"CVE-2026-90190","nvd":{"published":"2026-09-17T17:17:13.670","modified":"2026-10-19T09:19:09.013","status":"Received","description":"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 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.","cvss_v4":null,"cvss_v3":null,"cwes":[],"references":["https://git.kernel.org/stable/c/017dac7670909eaea3eb36e6b3b5a8be9ce0a14d","https://git.kernel.org/stable/c/0a8c2f7b95981913ac370683e34db4906970c210","https://git.kernel.org/stable/c/234117949da3b3f9705a21b66094f9f30bbe681d","https://git.kernel.org/stable/c/349903f7ee72f7ac5b7a98840d701b2082d140a3","https://git.kernel.org/stable/c/c7dea90c9b4ef1dfbd2e4df36de180c76fd7c33c"],"products":[],"source":"nvd","synced_at":"2026-10-19T22:55:23.253742848+00:00"},"epss":{"cve":"CVE-2026-90190","score":0.00205,"percentile":0.10437,"date":"2026-10-25"},"kev":null,"osv":[],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}