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CVE-2026-46147

Status: AnalyzedMedium (5.5)—

In the Linux kernel, the following vulnerability has been resolved:

KVM: arm64: Fix pin leak and publication ordering in __pkvm_init_vcpu()

Two bugs exist in the vCPU initialisation path:

Technical details traces, logs and code from the original report
1. If a check fails after hyp_pin_shared_mem() succeeds, the cleanup
   path jumps to 'unlock' without calling unpin_host_vcpu() or
   unpin_host_sve_state(), permanently leaking pin references on the
   host vCPU and SVE state pages.

   Extract a register_hyp_vcpu() helper that performs the checks and
   the store. When register_hyp_vcpu() returns an error, call
   unpin_host_vcpu() and unpin_host_sve_state() inline before falling
   through to the existing 'unlock' label.

2. register_hyp_vcpu() publishes the new vCPU pointer into
   'hyp_vm->vcpus[]' with a bare store, allowing a concurrent caller
   of pkvm_load_hyp_vcpu() to observe a partially initialised vCPU
   object.

   Ensure the store uses smp_store_release() and the load uses
   smp_load_acquire(). While 'vm_table_lock' currently serialises the
   store and the load, these barriers ensure the reader sees the fully
   initialised 'hyp_vcpu' object even if there were a lockless path or
   if the lock's own ordering guarantees were insufficient for nested
   object initialization.

CVSS

Exploitation probability (EPSS)

EPSS (Exploit Prediction Scoring System, FIRST) estimates how likely a vulnerability is to be exploited in the wild within 30 days. It complements CVSS (impact) and CISA KEV (confirmed exploitation).

Affected technologies (1)

Linux — Linux Kernel

CWEs

References

Raw JSON (NVD)

Show
{
  "id": "CVE-2026-46147",
  "cveTags": [],
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          "attackVector": "LOCAL",
          "baseSeverity": "MEDIUM",
          "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H",
          "integrityImpact": "NONE",
          "userInteraction": "NONE",
          "attackComplexity": "LOW",
          "availabilityImpact": "HIGH",
          "privilegesRequired": "LOW",
          "confidentialityImpact": "NONE"
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        "impactScore": 3.6,
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  "published": "2026-05-28T10:16:30.320",
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      "description": [
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          "value": "CWE-401"
        }
      ]
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  ],
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nKVM: arm64: Fix pin leak and publication ordering in __pkvm_init_vcpu()\n\nTwo bugs exist in the vCPU initialisation path:\n\n1. If a check fails after hyp_pin_shared_mem() succeeds, the cleanup\n   path jumps to 'unlock' without calling unpin_host_vcpu() or\n   unpin_host_sve_state(), permanently leaking pin references on the\n   host vCPU and SVE state pages.\n\n   Extract a register_hyp_vcpu() helper that performs the checks and\n   the store. When register_hyp_vcpu() returns an error, call\n   unpin_host_vcpu() and unpin_host_sve_state() inline before falling\n   through to the existing 'unlock' label.\n\n2. register_hyp_vcpu() publishes the new vCPU pointer into\n   'hyp_vm->vcpus[]' with a bare store, allowing a concurrent caller\n   of pkvm_load_hyp_vcpu() to observe a partially initialised vCPU\n   object.\n\n   Ensure the store uses smp_store_release() and the load uses\n   smp_load_acquire(). While 'vm_table_lock' currently serialises the\n   store and the load, these barriers ensure the reader sees the fully\n   initialised 'hyp_vcpu' object even if there were a lockless path or\n   if the lock's own ordering guarantees were insufficient for nested\n   object initialization."
    }
  ],
  "lastModified": "2026-06-17T10:53:08.980",
  "configurations": [
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        {
          "negate": false,
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}