{
  "cveId": "CVE-2026-99171",
  "url": "https://patchblox.com/security/cve/CVE-2026-99171",
  "summary": "CVE-2026-99171 is fixed in linux on 1 platform, first by DEBIAN-CVE-2026-99171, released November 3, 2026. It is not reported as exploited. Patch Radar priority: Routine.",
  "title": "ntfs3: free the sbi after a grace period",
  "description": "In the Linux kernel, the following vulnerability has been resolved:  ntfs3: free the sbi after a grace period  If the \u0022nocase\u0022 mount option ntfs3 uses custom hash and dentry compare functions. Both access ntfs3 superblock private information in rcu pathwalk. ntfs_put_super() and ntfs3_kill_sb() drop the info without any rcu delay. A lookup that\u0027s still inside the filesystem when the last reference to the mount is dropped causes a UAF. With a pathwalk held up in ntfs_d_hash() while the last reference to the mount goes away:    BUG: KASAN: slab-use-after-free in ntfs_nls_to_utf16\u002B0x752/0x940   Read of size 8 at addr ff1100010453c850 by task walker/99   Call Trace:    \u003CTASK\u003E    ntfs_nls_to_utf16\u002B0x752/0x940    ntfs_d_hash\u002B0x22b/0x500    link_path_walk\u002B0x11ad/0x1d30    path_lookupat\u002B0x63/0xb00    filename_lookup\u002B0x1f1/0x5b0    vfs_statx\u002B0xd7/0x3b0   [...]   Allocated by task 95:    __kmalloc_cache_noprof\u002B0x249/0x560    ntfs_init_fs_context\u002B0x2db/0x5a0    alloc_fs_context\u002B0x52e/0xc70   [...]   Freed by task 98:    kfree\u002B0x1db/0x5b0    deactivate_locked_super\u002B0x9c/0xf0    cleanup_mnt\u002B0x9f/0x130    task_work_run\u002B0x131/0x250  The bug is currently masked by the grace period in namespace_unlock() for umount(2). Keep the necessary information until the filesystem private info is freed and free it with an rcu delay.  ntfs3_free_sbi() now runs from an rcu callback and drops the upcase table via ntfs_put_shared(). So switch s_shared_lock over to spin_lock_bh(). Otherwise the callback can deadlock against a task holding the lock on the same cpu.",
  "published": "2026-10-28T11:17:37Z",
  "severity": "Moderate",
  "cvss": 4.7,
  "epss": 0.00174,
  "epssPercentile": 0.06922,
  "priority": "Routine",
  "priorityTier": 4,
  "exploited": false,
  "vendorExploited": false,
  "disclosed": false,
  "vendorAdvisory": "https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-99171",
  "fixes": [
    {
      "platform": "linux",
      "product": "linux",
      "release": "Debian 13.5 (trixie)",
      "fixedVersion": "6.12.115-2",
      "fix": "DEBIAN-CVE-2026-99171",
      "url": "https://patchblox.com/security/fix/linux/debian-cve-2026-99171",
      "released": "2026-11-03T18:58:21Z"
    },
    {
      "platform": "linux",
      "product": "linux",
      "release": "Debian 14",
      "fixedVersion": "7.2.13-1",
      "fix": "DEBIAN-CVE-2026-99171",
      "url": "https://patchblox.com/security/fix/linux/debian-cve-2026-99171",
      "released": "2026-11-03T18:58:21Z"
    }
  ],
  "noFixYet": [],
  "dataAsOf": "2026-11-08T19:12:23Z",
  "attribution": {
    "text": "Data: Patchblox Patch Radar",
    "url": "https://patchblox.com/security/patch-radar",
    "terms": "https://patchblox.com/security/patch-radar/use-the-data"
  }
}