{
  "affected": [
    {
      "ecosystem_specific": {
        "urgency": "not yet assigned"
      },
      "package": {
        "ecosystem": "Debian:12",
        "name": "linux"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "ecosystem_specific": {
        "urgency": "not yet assigned"
      },
      "package": {
        "ecosystem": "Debian:13",
        "name": "linux"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "ecosystem_specific": {
        "urgency": "not yet assigned"
      },
      "package": {
        "ecosystem": "Debian:14",
        "name": "linux"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "details": "In the Linux kernel, the following vulnerability has been resolved:  null_blk: use DEFINE_MUTEX for the file-scope mutex  In null_init(), mutex_init(\u0026lock) currently happens after configfs_register_subsystem(), which exposes the nullb subsystem to userspace. A racing mkdir() into /sys/kernel/config/nullb/ can reach null_find_dev_by_name() -\u003e mutex_lock(\u0026lock) before the mutex is initialized, trigger warning:  [  123.137788] DEBUG_LOCKS_WARN_ON(lock-\u003emagic != lock) [  123.137796] WARNING: kernel/locking/mutex.c:159 at mutex_lock+0x171/0x1c0, CPU#13: mkdir/1301 [  123.140090] Modules linked in: null_blk(+) nft_fib_inet nft_fib_ipv4 ...... [  123.154926] Call Trace: [  123.155172]  \u003cTASK\u003e [  123.155419]  ? __pfx_mutex_lock+0x10/0x10 [  123.156181]  ? __pfx__raw_spin_lock+0x10/0x10 [  123.156571]  nullb_group_make_group+0x20/0x100 [null_blk] [  123.157011]  configfs_mkdir+0x47b/0xc70 [  123.157337]  ? __pfx_configfs_mkdir+0x10/0x10 [  123.157719]  ? may_create_dentry+0x242/0x2e0 [  123.158061]  vfs_mkdir+0x2a9/0x6c0 [  123.158352]  filename_mkdirat+0x3dc/0x500 [  123.158710]  ? __pfx_filename_mkdirat+0x10/0x10 [  123.159070]  ? strncpy_from_user+0x3a/0x1d0 [  123.159413]  __x64_sys_mkdir+0x6b/0x90 [  123.159760]  do_syscall_64+0xea/0x600  Replace the runtime mutex_init(\u0026lock) with a static DEFINE_MUTEX(lock) declaration to fix this issue.",
  "id": "DEBIAN-CVE-2026-90190",
  "modified": "2026-09-18T04:47:31.166884934Z",
  "published": "2026-09-17T17:17:13.670Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://security-tracker.debian.org/tracker/CVE-2026-90190"
    }
  ],
  "upstream": [
    "CVE-2026-90190"
  ]
}