FKIE_CVE-2026-19574

Vulnerability from fkie_nvd - Published: 2026-10-09 08:16 - Updated: 2026-10-09 18:17
Severity
7.0 (High) - CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H
Summary
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.
References
vulnerabilities@zephyrproject.orghttps://github.com/zephyrproject-rtos/zephyr/commit/805054b8ed89dd5441fbca36b3cd3be7e4fb4100
vulnerabilities@zephyrproject.orghttps://github.com/zephyrproject-rtos/zephyr/security/advisories/GHSA-923h-8c2j-pcm5
Impacted products
Vendor Product Version
To clipboard 

{
  "affected": [
    {
      "affectedData": [
        {
          "collectionURL": "https://github.com/zephyrproject-rtos/zephyr",
          "defaultStatus": "unaffected",
          "packageName": "zephyr",
          "product": "zephyr",
          "programFiles": [
            "arch/arm64/core/mmu.c"
          ],
          "programRoutines": [
            {
              "name": "arch_mem_domain_init"
            },
            {
              "name": "k_mem_domain_init"
            }
          ],
          "vendor": "zephyrproject",
          "versions": [
            {
              "lessThanOrEqual": "4.4.2",
              "status": "affected",
              "version": "3.3.0",
              "versionType": "semver"
            }
          ]
        }
      ],
      "source": "vulnerabilities@zephyrproject.org"
    }
  ],
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "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\u0027s cached translations from another\u0027s in the TLB.\n\nThe 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 -\u003e B -\u003e 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.\n\nTriggering 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\u0027s partitions and thread stacks with that domain\u0027s permissions, defeating the memory-domain isolation boundary.\n\nThe 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."
    }
  ],
  "id": "CVE-2026-19574",
  "lastModified": "2026-10-09T18:17:08.147",
  "metrics": {
    "cvssMetricV31": [
      {
        "cvssData": {
          "attackComplexity": "HIGH",
          "attackVector": "LOCAL",
          "availabilityImpact": "HIGH",
          "baseScore": 7.0,
          "baseSeverity": "HIGH",
          "confidentialityImpact": "HIGH",
          "integrityImpact": "HIGH",
          "privilegesRequired": "LOW",
          "scope": "UNCHANGED",
          "userInteraction": "NONE",
          "vectorString": "CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H",
          "version": "3.1"
        },
        "exploitabilityScore": 1.0,
        "impactScore": 5.9,
        "source": "vulnerabilities@zephyrproject.org",
        "type": "Secondary"
      }
    ],
    "ssvcV203": [
      {
        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "ssvcData": {
          "id": "CVE-2026-19574",
          "options": [
            {
              "exploitation": "none"
            },
            {
              "automatable": "no"
            },
            {
              "technicalImpact": "total"
            }
          ],
          "role": "CISA Coordinator",
          "timestamp": "2026-10-09T17:56:13.062546Z",
          "version": "2.0.3"
        }
      }
    ]
  },
  "published": "2026-10-09T08:16:54.940",
  "references": [
    {
      "source": "vulnerabilities@zephyrproject.org",
      "url": "https://github.com/zephyrproject-rtos/zephyr/commit/805054b8ed89dd5441fbca36b3cd3be7e4fb4100"
    },
    {
      "source": "vulnerabilities@zephyrproject.org",
      "url": "https://github.com/zephyrproject-rtos/zephyr/security/advisories/GHSA-923h-8c2j-pcm5"
    }
  ],
  "sourceIdentifier": "vulnerabilities@zephyrproject.org",
  "vulnStatus": "Awaiting Analysis",
  "weaknesses": [
    {
      "description": [
        {
          "lang": "en",
          "value": "CWE-284"
        }
      ],
      "source": "vulnerabilities@zephyrproject.org",
      "type": "Secondary"
    }
  ]
}



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