CVE-2026-74632— Linux内核 huge_memory 竞态条件漏洞
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，已修复以下漏洞： mm/huge_memory：修复 huge_zero_pfn 竞态条件 补丁系列 “mm/huge_memory: fix huge_zero_pfn race”，版本 2。 在引用计数实现的 中存在一个微妙的竞态条件。 快速路径中的原子逻辑未能考虑到这样一个事实：回收器（shrinker，负责释放最后的 引用锁）可能在竞态的 在此处安装有效值之后，在 中将 覆写为 哨兵值。 这会导致 被正确设置，但 被错误设置，从而导致 以及随之而来的 将巨大零页 folio 错误地识
可能的 ATT&CK 技术 1 AI
T1499 · Endpoint Denial of Service影响版本矩阵 22
| 厂商 | 产品 | 版本范围 | 状态 |
|---|---|---|---|
| Linux | Linux | 3b77e8c8cde581dadab9a0f1543a347e24315f11< 9332b080ad57650d1dc582e54517f9fc78ef89cc |
affected |
3b77e8c8cde581dadab9a0f1543a347e24315f11< f3a874a903053c53fb53ba287ea9eacda69c68e8 |
affected | ||
3b77e8c8cde581dadab9a0f1543a347e24315f11< 6024f6d0d9b9ca5138bfc4ac6f6e4bdf616e42b3 |
affected | ||
3b77e8c8cde581dadab9a0f1543a347e24315f11< 105d04edbec83010df5728f74d17fd9c108e7553 |
affected | ||
3b77e8c8cde581dadab9a0f1543a347e24315f11< ab7e4b407c7f58d1a003134eff3841f303d5ccc2 |
affected | ||
3b77e8c8cde581dadab9a0f1543a347e24315f11< 33192a26cddea7a7e4ca66e5c3eebd36fa8be2bb |
affected | ||
fc1fbc5b017b6f5ef24a4a93f33cd022225e01c8 |
affected | ||
bd092a0f19423d7e9e81182314a96ecd6a14f3b7 |
affected | ||
| … +14 条更多 | |||
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一、 漏洞 CVE-2026-74632 基础信息
漏洞信息
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Vulnerability Title
mm/huge_memory: fix huge_zero_pfn race
来源: CVE Program / CVE List V5
Vulnerability Description
In the Linux kernel, the following vulnerability has been resolved:
mm/huge_memory: fix huge_zero_pfn race
Patch series "mm/huge_memory: fix huge_zero_pfn race", v2.
There is a subtle race in the reference-counted huge_zero_folio
implementation.
The fast path atomic logic fails to account for the fact that the shrinker
(which drops the final huge_zero_refcount pin) can overwrite huge_zero_pfn
with the ~0UL sentinel value in shrink_huge_zero_folio_scan() after a
racing get_huge_zero_folio() installed a valid value there.
This results in huge_zero_folio being correctly set but huge_zero_pfn
being set incorrectly and thus is_huge_zero_pfn() and consequently
is_huge_zero_pmd() will misidentify the huge zero folio as being an
ordinary THP folio.
This can result in the huge zero folio being split and otherwise treated
incorrectly.
The solution to this is very subtle as there is an atomic fast path, and
thus ordering in weakly ordered architectures has to be treated very
carefully.
The first commit fixes the issue by introducing a spinlock around
huge_zero_[pfn, folio, refcount] write, with careful consideration paid to
load/store ordering in the fast path. It is placed first and kept as
small as possible so that it can be backported on its own.
The second commit is a pure cleanup which reworks the
CONFIG_PERSISTENT_HUGE_ZERO_FOLIO logic to better separate the persistent
logic from the dynamically allocated one.
This patch (of 2):
If !CONFIG_PERSISTENT_HUGE_ZERO_FOLIO, the huge_zero_folio is refcounted
by huge_zero_refcount and returned by mm_get_huge_zero_folio().
When the caller is done with the huge zero page, its reference count is
decremented. Only a shrinker can set the reference count to zero.
A race can unfortunately occur between a shrinker decrementing the
reference count to zero and a concurrent page fault.
This is because shrink_huge_zero_folio_scan() might, if very unlucky, be
preempted between setting huge_zero_refcount to zero and writing an
invalid value.
During this time get_huge_zero_folio() could write to huge_zero_pfn before
shrink_huge_zero_folio_scan() resumes.
In this event the huge zero folio will be persistently misidentified
causing the THP code path to be entered inappropriately for the huge zero
folio:
CPU 0 CPU 1
=======================================|=================================
shrink_huge_zero_folio_scan() |
atomic_cmpxchg() sets refcount to 0 |
xchg() sets huge_zero_folio to NULL | get_huge_zero_folio()
| | atomic_inc_not_zero() -> zero
preempted for a long time | Allocate new huge zero folio
| | Write valid huge_zero_folio
v | Write valid huge_zero_pfn
Overwrite huge_zero_pfn with ~0UL <--- Invalid overwrite!
This results in is_huge_zero_pfn() and is_huge_zero_pmd() incorrectly
returning false for a huge zero page which could result in issues like the
huge zero folio being incorrectly split.
Note that the issue is with huge_zero_pfn not huge_zero_folio, as
get_huge_zero_folio() uses cmpxchg() gated on huge_zero_folio being NULL
with a retry loop and shrink_huge_zero_folio_scan() uses xchg() to set
huge_zero_folio.
Fix the issue by introducing a spinlock, huge_zero_lock, to prevent
concurrent write of huge_zero_folio, huge_zero_pfn and huge_zero_refcount.
There needs to be significant care taken here to ensure correctness:
The fast path in get_huge_zero_folio() uses atomic_inc_not_zero(), which
is outside of the critical section, and means huge zero allocation is
gated on zero huge_zero_refcount.
The fast path doesn't use huge_zero_lock, so the critical section is
irrelevant to it.
So invariants are required - huge_zero_refcount MUST:
* Only be set in the huge_zero_lock critical section to ensure
serialisation of huge_zero_pfn, huge_zero_folio and
---truncated---
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-2026-74632 的公开POC
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CVE-2026-74632 补丁与修复 (6)
同批安全公告 · Linux · 2026-08-22 · 共 150 条
| CVE-2026-74705 | 10.0 CRITICAL | UDP隧道分段潜在使用-after-free漏洞 |
| CVE-2026-74612 | 10.0 CRITICAL | Linux内核veth模块SKB长度计算漏洞 |
| CVE-2026-74587 | 9.8 CRITICAL | SCTP 缓存 ASCONF 块使用后释放漏洞 |
| CVE-2026-74591 | 9.8 CRITICAL | Linux 内核文件映射恢复索引前重试导致漏洞 |
| CVE-2026-74688 | 9.8 CRITICAL | SCTP传输控制块移除漏洞 |
| CVE-2026-74597 | 9.8 CRITICAL | Linux ip6_tunnel skb2->cb[]未清除漏洞 |
| CVE-2026-74617 | 9.8 CRITICAL | dibs: 在dibs_dev_alloc()中初始化dibs->lock |
| CVE-2026-74616 | 9.8 CRITICAL | Linux内核XDP克隆数据包越界漏洞 |
| CVE-2026-74628 | 9.8 CRITICAL | Linux内核 x25 远程计时器释放后使用漏洞 |
| CVE-2026-74608 | 9.8 CRITICAL | SMB客户端cifs_try_adding_channels函数中的释放后使用漏洞 |
| CVE-2026-74669 | 9.8 CRITICAL | Linux IPVS IPv4选项后重定位隧道ICMP错误 |
| CVE-2026-74662 | 9.8 CRITICAL | Linux inet frags 定时器竞争条件漏洞 |
| CVE-2026-74730 | 9.8 CRITICAL | NFS：在FREE_STATEID调用期间锁定struct nfs_server |
| CVE-2026-74727 | 9.8 CRITICAL | OpenVPN by_id移除后跳过哈希重构 |
| CVE-2026-74586 | 9.8 CRITICAL | Linux内核SCTP对等端移除时传输未清理漏洞 |
| CVE-2026-74723 | 9.8 CRITICAL | btrfs LZO拒绝无有效头部的内联扩展 |
| CVE-2026-74588 | 9.8 CRITICAL | Linux SCTP传输列表不同步漏洞 |
| CVE-2026-74611 | 9.8 CRITICAL | TLS 1.3 乐观重试消息迭代器恢复漏洞 |
| CVE-2026-74712 | 9.3 CRITICAL | mlx5 vdpa 在 create_direct_keys() 中缓冲区长度修复漏洞 |
| CVE-2026-74665 | 9.1 CRITICAL | NET skb长度计算通用XDP片段调整后修复 |
显示前 20 条，共 150 条。 查看全部 → →
IV. Related Vulnerabilities
V. Comments for CVE-2026-74632
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