CVE-2026-74632— Linux kernel 安全漏洞
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。
Linux kernel是美国Linux基金会开源的一个操作系统内核。 Linux kernel存在安全漏洞，该漏洞源于huge_zero_pfn引用计数实现中的竞态条件，原子快速路径逻辑未考虑shrinker覆盖huge_zero_pfn的情况，可能导致大零页被错误识别为普通THP folio并错误拆分。
可能的 ATT&CK 技术 1 AI
T1499 · Endpoint Denial of Service影响版本矩阵 25
| 厂商 | 产品 | 版本范围 | 状态 |
|---|---|---|---|
| Linux | Linux | 6527d8ef68c3ca3c455e38ae2a37cd7810caec73< 9c0fd1802ce06d7709f0bae4edeb085288f28764 |
affected |
3b77e8c8cde581dadab9a0f1543a347e24315f11< b7041ba61c5da4e0b56f9be58cfb87d7689724e4 |
affected | ||
3b77e8c8cde581dadab9a0f1543a347e24315f11< 9332b080ad57650d1dc582e54517f9fc78ef89cc |
affected | ||
3b77e8c8cde581dadab9a0f1543a347e24315f11< f3a874a903053c53fb53ba287ea9eacda69c68e8 |
affected | ||
3b77e8c8cde581dadab9a0f1543a347e24315f11< 6024f6d0d9b9ca5138bfc4ac6f6e4bdf616e42b3 |
affected | ||
3b77e8c8cde581dadab9a0f1543a347e24315f11< 105d04edbec83010df5728f74d17fd9c108e7553 |
affected | ||
3b77e8c8cde581dadab9a0f1543a347e24315f11< ab7e4b407c7f58d1a003134eff3841f303d5ccc2 |
affected | ||
3b77e8c8cde581dadab9a0f1543a347e24315f11< 33192a26cddea7a7e4ca66e5c3eebd36fa8be2bb |
affected | ||
| … +17 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
Vulnerability Title
Linux kernel 安全漏洞
来源: 中国国家信息安全漏洞库 CNNVD
Vulnerability Description
Linux kernel是美国Linux基金会开源的一个操作系统内核。 Linux kernel存在安全漏洞，该漏洞源于huge_zero_pfn引用计数实现中的竞态条件，原子快速路径逻辑未考虑shrinker覆盖huge_zero_pfn的情况，可能导致大零页被错误识别为普通THP folio并错误拆分。
来源: 中国国家信息安全漏洞库 CNNVD
CVSS Information
N/A
来源: 中国国家信息安全漏洞库 CNNVD
Vulnerability Type
N/A
来源: 中国国家信息安全漏洞库 CNNVD
受影响产品
二、漏洞 CVE-2026-74632 的公开POC
| # | POC 描述 | 源链接 | 神龙链接 |
|---|
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CVE-2026-74632 补丁与修复 (6)
CVE-2026-74632 其他参考 (2)
同批安全公告 · Linux · 2026-08-22 · 共 149 条
| CVE-2026-74612 | 10.0 CRITICAL | Linux kernel 安全漏洞 |
| CVE-2026-74705 | 10.0 CRITICAL | Linux kernel 安全漏洞 |
| CVE-2026-74628 | 9.8 CRITICAL | Linux kernel 安全漏洞 |
| CVE-2026-74688 | 9.8 CRITICAL | Linux kernel 安全漏洞 |
| CVE-2026-74617 | 9.8 CRITICAL | Linux kernel 安全漏洞 |
| CVE-2026-74616 | 9.8 CRITICAL | Linux kernel 安全漏洞 |
| CVE-2026-74611 | 9.8 CRITICAL | Linux kernel 安全漏洞 |
| CVE-2026-74608 | 9.8 CRITICAL | Linux kernel 安全漏洞 |
| CVE-2026-74723 | 9.8 CRITICAL | Linux kernel 安全漏洞 |
| CVE-2026-74662 | 9.8 CRITICAL | Linux kernel 安全漏洞 |
| CVE-2026-74727 | 9.8 CRITICAL | Linux kernel 安全漏洞 |
| CVE-2026-74597 | 9.8 CRITICAL | Linux kernel 安全漏洞 |
| CVE-2026-74591 | 9.8 CRITICAL | Linux kernel 安全漏洞 |
| CVE-2026-74586 | 9.8 CRITICAL | Linux kernel 安全漏洞 |
| CVE-2026-74587 | 9.8 CRITICAL | Linux kernel 安全漏洞 |
| CVE-2026-74588 | 9.8 CRITICAL | Linux kernel 安全漏洞 |
| CVE-2026-74669 | 9.8 CRITICAL | Linux kernel 安全漏洞 |
| CVE-2026-74730 | 9.8 CRITICAL | Linux kernel 安全漏洞 |
| CVE-2026-74712 | 9.3 CRITICAL | Linux kernel 安全漏洞 |
| CVE-2026-74665 | 9.1 CRITICAL | Linux kernel 安全漏洞 |
显示前 20 条，共 149 条。 查看全部 → →
IV. Related Vulnerabilities
V. Comments for CVE-2026-74632
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