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CVE-2026-19574— ARM64 MMU can assign an in-use ASID to a new memory domain, breaking user-mode memory isolation

Quick assessment

Affected
zephyrproject zephyr
Exploitation
No confirmed in-the-wild exploitation; assess based on exposure
Recommended action
Check the vendor advisory and references for a fixed version. If immediate upgrade is impossible, restrict exposure and increase monitoring.

ARM64 MMU 后端在 （位于 ）中，使用简单的循环计数器（bare round-robin counter）为内存域分配地址空间标识符（ASIDs）。由于 设置为 8，因此总共只有 255 个可用的 ASID。一旦计数器发生回绕（wrap）， 可能会将一个已被当前存活域占用的 ASID 分配给一个新的域。由于域私有映射是以非全局方式（MT_NG）安装的，ASID 成为 TLB 中区分不同域的缓存翻译条目的唯一标签。 在上下文切换路径 中，仅当退出域和进入域具有相同的 ASID 时才会刷新 TLB。这一机制未能

CVSS 7.0 · High

Possible ATT&CK Techniques 1 AI

T1079
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I. Basic Information for CVE-2026-19574

Vulnerability Information
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Vulnerability Title
ARM64 MMU can assign an in-use ASID to a new memory domain, breaking user-mode memory isolation
Source: CVE Program / CVE List V5
Vulnerability Description
The ARM64 MMU back-end allocated address space identifiers (ASIDs) for memory domains with a bare round-robin counter in arch_mem_domain_init() (arch/arm64/core/mmu.c). VM_ASID_BITS is 8, so only 255 ASIDs exist; once the counter wrapped, arch_mem_domain_init() could hand an ASID to a new domain while a still-live domain held the same one. Domain-private mappings are installed non-global (MT_NG), so the ASID is the only tag separating one domain's cached translations from another's in the TLB. The context-switch path in z_arm64_swap_ptables() only flushes the TLB when the outgoing and incoming domains carry the same ASID, which does not cover a duplicate reached through a third domain: for domains A and C sharing an ASID and an unrelated domain B, the schedule A -> B -> C never takes the flush branch, so the ASID-tagged entries A populated remain resident while C runs. Under SMP two live domains sharing an ASID can additionally be resident on two CPUs at once, which the architecture does not allow for distinct translation-table sets. Triggering the wrap requires a CONFIG_USERSPACE application on ARM64 that creates more than 255 memory domains over its lifetime; k_mem_domain_init() and k_mem_domain_deinit() are supervisor-only APIs and are not exposed as syscalls, so an unprivileged thread cannot drive the counter directly. Once two live domains alias, however, a user-mode thread in one domain can read and write memory belonging to the other domain's partitions and thread stacks with that domain's permissions, defeating the memory-domain isolation boundary. The fix scans the live domain_list before assigning an ASID, advances the round-robin counter past ASIDs already in use, and returns -ENOMEM when all are taken, so domain creation fails closed instead of silently aliasing.
Source: CVE Program / CVE List V5
CVSS Information
CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H
Source: CVE Program / CVE List V5
Vulnerability Type
访问控制不恰当
Source: CVE Program / CVE List V5

Affected Products

Vendor Product Affected Versions CPE Subscribe
zephyrproject zephyr 3.3.0 ~ 4.4.2 -

II. Public POCs for CVE-2026-19574

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III. Intelligence Information for CVE-2026-19574

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Patches & Fixes for CVE-2026-19574 (1)

Vendor Advisories for CVE-2026-19574 (1)

Same Patch Batch · zephyrproject · 2026-10-09 · 5 CVEs total

CVE-2026-19570 8.8 HIGH Out-of-bounds write in LE Audio Broadcast Sink when copying BASE subgroup metadata into th
CVE-2026-19569 8.8 HIGH Integer overflow in dynamic kernel object allocation allows user-mode threads to corrupt t
CVE-2026-19575 7.8 HIGH Type confusion in the device_deinit system call allows user-mode threads to execute arbitr
CVE-2026-19571 6.7 MEDIUM Race condition in ITE IT8xxx2 SHI host-command backend lets a second SPI request write an

IV. Related Vulnerabilities

Same product: zephyr
Same vendor: zephyrproject
Same weakness: CWE-284

V. Comments for CVE-2026-19574

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