CVE-2026-98991

Что произошло

In the Linux kernel, the following vulnerability has been resolved: namespace: queue a mount only once for mount notifications mnt_notify_add() puts a mount on notify_list. It doesn't check whether the mount is on the list already. That's fine as long as every mount is queued at most once per namespace_sem hold. It isn't. propagate_umount() moves a surviving overmount off a stack of mounts that are going away and queues it as moved. shrink_submounts() and mark_mounts_for_expiry() call umount_tree() for several mounts under a single namespace_sem hold. So the second umount_tree() can take down exactly the mount the first one reparented, reparent it once more and so end up queueing it a second time. The second list_add_tail() cuts the mounts queued in between out of the list while the head still points at the last of them. notify_mnt_list() then only visits that one mount and the others are freed after the grace period with notify_list still pointing at them. Every later mount operation on the host walks freed memory: BUG: KASAN: slab-use-after-free in __list_add_valid_or_report Read of size 8 at addr ffff8881003d57e0 by task notify_dq/162 __list_add_valid_or_report+0x15c/0x1a0 mnt_add_to_ns+0x322/0x890 attach_recursive_mnt.isra.0+0xf2a/0x1a00 path_mount+0x139c/0x1d40 This needs a mount with MNT_SHRINKABLE to bind from. That's what finish_automount() creates (submounts of NFS, AFS and CIFS and the tracefs mount below debugfs). Bind mounts inherit the flag. A mount namespace with a FAN_MARK_MNTNS mark does the rest and root in a user namespace can have both. Initialize to_notify in alloc_vfsmnt() and leave a mount alone that is queued already. mnt_notify() looks at the state the mount has when the list is drained so a single entry per mount is enough. The move event for a mount that is unmounted under the same hold is lost. That's fine. The detach is what matters.

Что делать

dpkg-query -W -f='${Package}	${Version}\n'

rpm -qa --qf '%{NAME}\t%{VERSION}-%{RELEASE}\n'

Get-HotFix | Select-Object HotFixID, InstalledOn

Продукты и затронутые версии

{
  "status": "affected",
  "version": "bf630c40164162ba1d3933c2f5e3397d083e0948",
  "lessThan": "acbe9e4418e2ef7bef1a12e62e0e7d6145a15190",
  "versionType": "git"
}

{
  "status": "affected",
  "version": "bf630c40164162ba1d3933c2f5e3397d083e0948",
  "lessThan": "702ff3fe499876e09c45558a05366d21a5bc41ab",
  "versionType": "git"
}

{
  "status": "affected",
  "version": "bf630c40164162ba1d3933c2f5e3397d083e0948",
  "lessThan": "bd2feb7796b6585938a4241e7b7c4148a6f7b762",
  "versionType": "git"
}

{
  "status": "affected",
  "version": "6.15"
}

{
  "status": "unaffected",
  "version": "0",
  "lessThan": "6.15",
  "versionType": "semver"
}

{
  "status": "unaffected",
  "version": "6.18.57",
  "versionType": "semver",
  "lessThanOrEqual": "6.18.*"
}

{
  "status": "unaffected",
  "version": "7.2.11",
  "versionType": "semver",
  "lessThanOrEqual": "7.2.*"
}

{
  "status": "unaffected",
  "version": "7.3",
  "versionType": "original_commit_for_fix",
  "lessThanOrEqual": "*"
}

CVSS: оценки и векторы

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Источники и ссылки

{
  "cwes": [],
  "epss": {
    "source": "epss",
    "received_at": "2026-11-01T21:13:22.701776+00:00"
  },
  "title": {
    "source": "cve",
    "received_at": "2026-10-28T20:17:16.447779+00:00"
  },
  "scores": [
    "cve"
  ],
  "status": {
    "source": "cve",
    "received_at": "2026-10-28T20:17:16.447779+00:00"
  },
  "affected": [
    "cve"
  ],
  "published": {
    "source": "cve",
    "received_at": "2026-10-28T20:17:16.447779+00:00"
  },
  "solutions": [],
  "percentile": {
    "source": "epss",
    "received_at": "2026-11-01T21:13:22.701776+00:00"
  },
  "references": [
    "cve"
  ],
  "description": {
    "source": "cve",
    "received_at": "2026-10-28T20:17:16.447779+00:00"
  },
  "workarounds": [],
  "configurations": []
}

Хронология записи

1. Данные обновлены02.11.2026, 00:13
2. Данные обновлены31.10.2026, 12:00
3. Данные обновлены29.10.2026, 12:47
4. Опубликована28.10.2026, 23:17

Личная заметка и статус

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