CVE-2026-89928— KVM x86/mmu 无锁 rmap 遍历缺陷
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，以下漏洞已得到解决： KVM: x86/mmu: 在无锁 rmap 遍历中消费已加锁的 rmap 值 故意在观察到空的 rmap 时省略（elide）rmap 锁。在这种情况下， 也会重新启用抢占（preemption）并返回零，因此调用者既未持有 rmap 锁，也未持有抢占引用。该省略（elision）所依赖的不变量（invariant）被记录如下： > 如果 rmap 为空，则省略锁。因为无锁遍历器（只读模式）既无需也无法遍历空的 rmap，也无法向 rmap 添加条目。换言之，只有那些
可能的 ATT&CK 技术 1 AI
T1562.008影响版本矩阵 8
| 厂商 | 产品 | 版本范围 | 状态 |
|---|---|---|---|
| Linux | Linux | af3b6a9eba48419732b07a0472db7160282f0f39< 41debfc98526c0a95c41a62435aca0a70340a26d |
affected |
af3b6a9eba48419732b07a0472db7160282f0f39< 8edb3c09e43f7cd8a5dfd291c6e0fc9c74d4621d |
affected | ||
af3b6a9eba48419732b07a0472db7160282f0f39< e428f9779a43737d830111238816f1928b07aefb |
affected | ||
6.15 |
affected | ||
< 6.15 |
unaffected | ||
6.18.51≤ 6.18.* |
unaffected | ||
7.2.5≤ 7.2.* |
unaffected | ||
7.3-rc1≤ * |
unaffected |
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一、 漏洞 CVE-2026-89928 基础信息
漏洞信息
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Vulnerability Title
KVM: x86/mmu: Consume the locked rmap value in the lockless rmap walk
来源: CVE Program / CVE List V5
Vulnerability Description
In the Linux kernel, the following vulnerability has been resolved:
KVM: x86/mmu: Consume the locked rmap value in the lockless rmap walk
__kvm_rmap_lock() deliberately elides the rmap lock when it observes an
empty rmap. In that case kvm_rmap_lock_readonly() also re-enables
preemption and returns zero, so the caller holds neither the rmap lock
nor a preemption reference. The elision documents the invariant it
relies on:
* Elide the lock if the rmap is empty, as lockless walkers (read-only
* mode) don't need to (and can't) walk an empty rmap, nor can they add
* entries to the rmap. I.e. the only paths that process empty rmaps
* do so while holding mmu_lock for write, and are mutually exclusive.
kvm_rmap_age_gfn_range() ignores the returned value and unconditionally
enters for_each_rmap_spte_lockless(). The iterator started with
rmap_get_first(), which re-reads rmap_head->val rather than using the
value returned by the lock. If a writer populates the rmap between the
lock's read and the iterator's re-read, the aging path walks the newly
installed rmap without holding its lock.
For a KVM_RMAP_MANY rmap this leaves the walker following a
pte_list_desc chain that it never locked. A writer holding mmu_lock for
write may free that chain (e.g. kvm_zap_all_rmap_sptes() on the recycle
path, or any rmap zap) via kmem_cache_free() while the walk is in
progress, giving a slab use-after-free. Nothing serialises the two: the
aging path runs without mmu_lock when CONFIG_KVM_MMU_LOCKLESS_AGING=y,
and the rmap lock that would otherwise exclude the writer was elided.
Because the empty path re-enables preemption, the interval between the
two reads can span an arbitrary scheduling delay.
Fix the class of bug by having the lockless walk consume the value
returned by the lock instead of re-reading the rmap. Split
rmap_get_first() into __rmap_get_first(), which starts an iterator from
an already-read rmap value, and make for_each_rmap_spte_lockless() take
that value and call __rmap_get_first() directly.
kvm_rmap_age_gfn_range() passes the value returned by
kvm_rmap_lock_readonly(): when the lock was elided the value is zero,
__rmap_get_first() returns NULL, and the walk is skipped. No lockless
walker re-reads the rmap, so the lock-elision invariant cannot be
violated, and no lock()-without-paired-unlock() path is added to the
aging code.
来源: CVE Program / CVE List V5
CVSS Information
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/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-2026-89928 的公开POC
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|---|
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CVE-2026-89928 其他参考 (3)
同批安全公告 · Linux · 2026-09-16 · 共 276 条
| CVE-2026-90048 | 9.8 CRITICAL | Linux内核NTFS3文件系统越界写漏洞 |
| CVE-2026-90012 | 9.8 CRITICAL | SPI DMA映射所有权修复 |
| CVE-2026-89970 | 9.8 CRITICAL | NVM Target SQ拆除时超时工作未同步 |
| CVE-2026-89857 | 9.8 CRITICAL | QLogic qla2xxx NVMe LS拒绝竞态条件漏洞 |
| CVE-2026-89969 | 9.8 CRITICAL | Linux内核 nvmet-tcp 越界写入漏洞 |
| CVE-2026-89847 | 9.8 CRITICAL | qla2xxx SCSI驱动异步IOCB超时双重完成漏洞 |
| CVE-2026-89972 | 9.8 CRITICAL | NVMe驱动错误路径SRCU宽限期缺失漏洞 |
| CVE-2026-89990 | 9.8 CRITICAL | Ceph ceph_mds_check_access 互斥锁缺失漏洞 |
| CVE-2026-90036 | 9.8 CRITICAL | Linux NFSd 阻塞锁收割时释放后使用漏洞 |
| CVE-2026-90038 | 9.8 CRITICAL | Linux内核NFSD导出撤销后使用漏洞 |
| CVE-2026-90037 | 9.8 CRITICAL | Linux内核NFSD close_lru释放后使用漏洞 |
| CVE-2026-89788 | 9.8 CRITICAL | Linux kernel ksmbd 释放后使用漏洞 |
| CVE-2026-89783 | 9.8 CRITICAL | Linux内核 xfrm6 越界写入漏洞 |
| CVE-2026-90042 | 9.8 CRITICAL | Ceph 虚拟内存分配缓冲区文件名解密漏洞 |
| CVE-2026-89778 | 9.8 CRITICAL | isofs 空 zisofs 块页面数组越界访问漏洞 |
| CVE-2026-89915 | 9.3 CRITICAL | KVM arm64 移除虚拟机级 VNCR 映射计数器 |
| CVE-2026-90049 | 9.3 CRITICAL | 内核网络子系统中skb_zerocopy处理中的缺陷 |
| CVE-2026-89775 | 9.3 CRITICAL | KVM arm64 VNCR TLB大小计算漏洞 |
| CVE-2026-89916 | 9.3 CRITICAL | KVM arm64 VNCR失效重试漏洞 |
| CVE-2026-89930 | 9.3 CRITICAL | KVM嵌套虚拟化本地TLB刷新漏洞 |
显示前 20 条，共 276 条。 查看全部 → →
IV. Related Vulnerabilities
V. Comments for CVE-2026-89928
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