{
  "cveId": "CVE-2026-98985",
  "url": "https://patchblox.com/security/cve/CVE-2026-98985",
  "summary": "CVE-2026-98985 is fixed in linux on 1 platform, first by DEBIAN-CVE-2026-98985, released October 24, 2026. It is not reported as exploited. Patch Radar priority: Routine.",
  "title": "namespace: check the mounts before reading their parents in pivot_root()",
  "description": "In the Linux kernel, the following vulnerability has been resolved:  namespace: check the mounts before reading their parents in pivot_root()  path_pivot_root() reads the parents of new_root and of the caller\u0027s root and checks whether they are shared before it checks that either mount is in the caller\u0027s mount namespace. Only namespace_sem is held. That\u0027s fine for a mount that is in the caller\u0027s mount namespace.  But new_root can be a file descriptor to a mount that has been unmounted and that only the file descriptor keeps alive. If that mount stayed attached to its parent when it was unmounted nothing pins the parent for it. The final mntput() of the parent unhooks the children under mount_lock alone and frees the parent afterwards:    pivot_root()                     close(fd), last ref on the parent   ------------                     ---------------------------------   ex_parent = new_mnt-\u003Emnt_parent                                    mntput_no_expire_slowpath()                                      __umount_mnt(new_mnt)                                    cleanup_mnt()                                      call_rcu()   IS_MNT_SHARED(ex_parent)    BUG: KASAN: slab-use-after-free in path_pivot_root\u002B0xf1a/0x1840   Read of size 4 at addr ffff8881047382f8 by task pivot_widen/157    path_pivot_root\u002B0xf1a/0x1840    __x64_sys_pivot_root\u002B0x165/0x190  The same goes for the caller\u0027s root via chroot(). Both outcomes of the check end in EINVAL so nothing but the read itself goes wrong. It\u0027s the same thing commit bb4609405752 (\u0022statmount: read the parent of an unmounted mount under mount_lock\u0022) fixed for statmount().  Check that both mounts are in the caller\u0027s namespace before their parents are read. Every path returns EINVAL either way.",
  "published": "2026-10-23T13:17:20Z",
  "severity": "Moderate",
  "cvss": 4.7,
  "epss": 0.00177,
  "epssPercentile": 0.07337,
  "priority": "Routine",
  "priorityTier": 4,
  "exploited": false,
  "vendorExploited": false,
  "disclosed": false,
  "vendorAdvisory": "https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-98985",
  "fixes": [
    {
      "platform": "linux",
      "product": "linux",
      "release": "Debian 13.5 (trixie)",
      "fixedVersion": "6.12.115-2",
      "fix": "DEBIAN-CVE-2026-98985",
      "url": "https://patchblox.com/security/fix/linux/debian-cve-2026-98985",
      "released": "2026-10-24T13:25:57Z"
    },
    {
      "platform": "linux",
      "product": "linux",
      "release": "Debian 14",
      "fixedVersion": "7.2.11-1",
      "fix": "DEBIAN-CVE-2026-98985",
      "url": "https://patchblox.com/security/fix/linux/debian-cve-2026-98985",
      "released": "2026-10-24T13:25:57Z"
    }
  ],
  "noFixYet": [],
  "dataAsOf": "2026-11-08T00:53:09Z",
  "attribution": {
    "text": "Data: Patchblox Patch Radar",
    "url": "https://patchblox.com/security/patch-radar",
    "terms": "https://patchblox.com/security/patch-radar/use-the-data"
  }
}