CVE-2026-98993— Linux 内核命名空间 clone_mnt 挂载点继承漏洞
一分钟漏洞结论
影响对象
Linux Linux
利用判断
尚无明确在野利用证据，仍需结合暴露面评估
建议动作
优先检查厂商安全公告和参考链接中的修复版本；无法立即升级时，限制受影响服务暴露并加强监测。
在 Linux 内核中，以下漏洞已得到修复： 命名空间（namespace）：在 clone_mnt() 中不再继承 MNT_UMOUNT 标志 MNT_UMOUNT 标志会在 或 将某个挂载点从其命名空间中移除时被置位，且该标志永远不会被清除。 函数对于携带该标志的挂载点，执行的是“取消链接”（unhook）操作，而非真正的卸载（unmount）。 允许已卸载的子挂载点保持连接，仅当其父挂载点携带该标志时； 则将该标志视为挂载点即将被卸载的信号，以此决定其他可卸载的挂载点、锁定挂载链的终点，以及是否需要为覆盖挂载
影响版本矩阵 14
| 厂商 | 产品 | 版本范围 | 状态 |
|---|---|---|---|
| Linux | Linux | 590ce4bcbfb4e0462a720a4ad901e84416080bba< 99698cfa34e493fc091219056aae446fe9442a96 |
affected |
590ce4bcbfb4e0462a720a4ad901e84416080bba< c26c1a91ad2881a194f7af543e0b57f0870006b2 |
affected | ||
590ce4bcbfb4e0462a720a4ad901e84416080bba< eecc9cd0fc07dba3f7fb0b2f844b4029435a2f7b |
affected | ||
590ce4bcbfb4e0462a720a4ad901e84416080bba< 5077b52e9e4d72da53c50251296b99cd416765a1 |
affected | ||
590ce4bcbfb4e0462a720a4ad901e84416080bba< e2c6d326216642011da318b9edfd5d57ebd5a56f |
affected | ||
7052e71b2d085f76800115d4a212dcaf82b86262 |
affected | ||
4.0.2< 4.1 |
affected | ||
4.1 |
affected | ||
| … +6 条更多 | |||
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一、 漏洞 CVE-2026-98993 基础信息
漏洞信息
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Vulnerability Title
namespace: don't inherit MNT_UMOUNT in clone_mnt()
来源: CVE Program / CVE List V5
Vulnerability Description
In the Linux kernel, the following vulnerability has been resolved:
namespace: don't inherit MNT_UMOUNT in clone_mnt()
MNT_UMOUNT gets raised on a mount that umount_tree() or umount_one() has
taken out of its namespace. It's never cleared. __detach_mounts()
unhooks a mount that carries it instead of unmounting it.
disconnect_mount() lets an unmounted child stay attached only if its
parent carries it. propagate_umount() takes it as the sign that a mount
is going to be unmounted when it decides what else can be unmounted,
where a chain of locked mounts ends and where a for reparenting an
overmount.
clone_mnt() copies the flags of the source and only masks
MNT_INTERNAL_FLAGS which doesn't include MNT_UMOUNT. A mount that was
lazily unmounted but is kept alive by a file descriptor can still be
copied when its root is an nsfs or pidfs file because may_copy_tree()
accepts those before checking whether the source is mounted at all:
mount --bind /proc/self/ns/net /tmp/x
exec 3< /tmp/x
umount -l /tmp/x
mount --bind /proc/self/fd/3 /tmp/y
The mount on /tmp/y is attached to the caller's namespace with
MNT_UMOUNT already set and every copy of it inherits the flag again.
That causes a number of bugs:
- Unlink its mountpoint from a mount namespace where it isn't one.
__detach_mounts() takes it for a mount that was unmounted earlier,
unhooks it from its parent and drops the reference the namespace
holds on it. It stays in the namespace with one reference too few
and as its own parent, so it can't be unmounted through the file
descriptor anymore and the namespace never finds it again. When the
namespace goes away it's leaked and points to a freed struct
mnt_namespace that may_change_propagation() and anon_ns_root() read
on the next propagation change or mount_setattr() through the file
descriptor.
- Make it shared and unmount a peer. trace_transfers() follows the
flag from the peer into it and strips it from its peer group.
- Let a propagated umount reach it. gather_candidates() marks it with
T_UMOUNT_CANDIDATE but never puts it on the candidate list, so the
mark is never cleared and every later propagated umount skips it. If
it's the parent of a locked mount handle_locked() takes it as the
cutoff and commits the locked child that should have stayed and
disconnect_mount() leaves that child attached to it, unmounted under
a mounted parent, which is what disconnect_mount() exists to
prevent. When the namespace goes away umount_tree() visits the child
a second time. And once __detach_mounts() has made it its own parent
reparent() never finds the end of the chain of unmounted parents.
A clone is a new mount that has never been unmounted. Add MNT_UMOUNT
to MNT_INTERNAL_FLAGS so clone_mnt() never copies it. And warn when
umount_tree() reaches a mount that already has it set.
来源: CVE Program / CVE List V5
CVSS Information
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
来源: CVE Program / CVE List V5
Vulnerability Type
N/A
来源: CVE Program / CVE List V5
受影响产品
二、漏洞 CVE-2026-98993 的公开POC
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CVE-2026-98993 补丁与修复 (5)
同批安全公告 · Linux · 2026-10-23 · 共 218 条
| CVE-2026-98959 | 9.8 CRITICAL | btrfs 扩展属性替换处理远程代码执行漏洞 |
| CVE-2026-99079 | 9.8 CRITICAL | Mellanox mlx5e 驱动 XSK 缓冲区释放漏洞 |
| CVE-2026-99078 | 9.8 CRITICAL | Mellanox mlx5e MPWQE重试时XSK缓冲区释放漏洞 |
| CVE-2026-98870 | 8.8 HIGH | ksmbd 会话清理时存在通道移除逻辑漏洞 |
| CVE-2026-98980 | 8.8 HIGH | namei 遍历中过度挂载条目信息泄露漏洞 |
| CVE-2026-99083 | 8.8 HIGH | ksmbd 的 krb5_authenticate() 函数堆越界写漏洞 |
| CVE-2026-99082 | 8.8 HIGH | KVM x86 内存管理漏洞 |
| CVE-2026-98981 | 8.8 HIGH | Linux 内核命名空间 dentry 解挂载前未哈希漏洞 |
| CVE-2026-98988 | 8.8 HIGH | Linux 5.13 命名空间越界漏洞 |
| CVE-2026-98978 | 8.4 HIGH | Linux 命名空间 锁定挂载永不失效漏洞 |
| CVE-2026-99042 | 8.4 HIGH | io_uring 24 字节 sockaddr_in6 过滤字段填充漏洞 |
| CVE-2026-98968 | 8.1 HIGH | AMT 中继通用查询远程代码执行漏洞 |
| CVE-2026-99064 | 8.1 HIGH | CIPSO 缓存选项偏移调整漏洞 |
| CVE-2026-99051 | 7.8 HIGH | fsverity 信息结构释放延迟漏洞 |
| CVE-2026-99050 | 7.8 HIGH | GPIO MPSSE 驱动 IRQ 轮询竞态漏洞 |
| CVE-2026-98975 | 7.8 HIGH | XFS 文件系统 reflink 标志交换逻辑漏洞 |
| CVE-2026-99053 | 7.8 HIGH | Linux TIPC 节点引用漏洞 |
| CVE-2026-99054 | 7.8 HIGH | Linux TIPC 拓扑服务队列资源泄漏漏洞 |
| CVE-2026-98974 | 7.8 HIGH | XFS 文件系统范围交换到文件末尾大小漏洞 |
| CVE-2026-98944 | 7.8 HIGH | Steam HID 注册重构漏洞 |
显示前 20 条，共 218 条。 查看全部 → →
IV. Related Vulnerabilities
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