CVE-2026-23425 (GCVE-0-2026-23425)

Vulnerability from cvelistv5 – Published: 2026-04-03 13:24 – Updated: 2026-04-13 06:07
VLAI?
Title
KVM: arm64: Fix ID register initialization for non-protected pKVM guests
Summary
In the Linux kernel, the following vulnerability has been resolved: KVM: arm64: Fix ID register initialization for non-protected pKVM guests In protected mode, the hypervisor maintains a separate instance of the `kvm` structure for each VM. For non-protected VMs, this structure is initialized from the host's `kvm` state. Currently, `pkvm_init_features_from_host()` copies the `KVM_ARCH_FLAG_ID_REGS_INITIALIZED` flag from the host without the underlying `id_regs` data being initialized. This results in the hypervisor seeing the flag as set while the ID registers remain zeroed. Consequently, `kvm_has_feat()` checks at EL2 fail (return 0) for non-protected VMs. This breaks logic that relies on feature detection, such as `ctxt_has_tcrx()` for TCR2_EL1 support. As a result, certain system registers (e.g., TCR2_EL1, PIR_EL1, POR_EL1) are not saved/restored during the world switch, which could lead to state corruption. Fix this by explicitly copying the ID registers from the host `kvm` to the hypervisor `kvm` for non-protected VMs during initialization, since we trust the host with its non-protected guests' features. Also ensure `KVM_ARCH_FLAG_ID_REGS_INITIALIZED` is cleared initially in `pkvm_init_features_from_host` so that `vm_copy_id_regs` can properly initialize them and set the flag once done.
Severity ?
No CVSS data available.
Assigner
References
Impacted products
Vendor Product Version
Linux Linux Affected: 41d6028e28bd474298ff10409c292ec46cf43a90 , < bce3847f7c51b86332bf2e554c9e80ca3820f16c (git)
Affected: 41d6028e28bd474298ff10409c292ec46cf43a90 , < 858620655c1fbff05997e162fc7d83a3293d5142 (git)
Affected: 41d6028e28bd474298ff10409c292ec46cf43a90 , < 7e7c2cf0024d89443a7af52e09e47b1fe634ab17 (git)
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    Linux Linux Affected: 6.14
Unaffected: 0 , < 6.14 (semver)
Unaffected: 6.18.17 , ≤ 6.18.* (semver)
Unaffected: 6.19.7 , ≤ 6.19.* (semver)
Unaffected: 7.0 , ≤ * (original_commit_for_fix)
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{
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      "affected": [
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          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "arch/arm64/kvm/hyp/nvhe/pkvm.c"
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              "operator": "OR"
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          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nKVM: arm64: Fix ID register initialization for non-protected pKVM guests\n\nIn protected mode, the hypervisor maintains a separate instance of\nthe `kvm` structure for each VM. For non-protected VMs, this structure is\ninitialized from the host\u0027s `kvm` state.\n\nCurrently, `pkvm_init_features_from_host()` copies the\n`KVM_ARCH_FLAG_ID_REGS_INITIALIZED` flag from the host without the\nunderlying `id_regs` data being initialized. This results in the\nhypervisor seeing the flag as set while the ID registers remain zeroed.\n\nConsequently, `kvm_has_feat()` checks at EL2 fail (return 0) for\nnon-protected VMs. This breaks logic that relies on feature detection,\nsuch as `ctxt_has_tcrx()` for TCR2_EL1 support. As a result, certain\nsystem registers (e.g., TCR2_EL1, PIR_EL1, POR_EL1) are not\nsaved/restored during the world switch, which could lead to state\ncorruption.\n\nFix this by explicitly copying the ID registers from the host `kvm` to\nthe hypervisor `kvm` for non-protected VMs during initialization, since\nwe trust the host with its non-protected guests\u0027 features. Also ensure\n`KVM_ARCH_FLAG_ID_REGS_INITIALIZED` is cleared initially in\n`pkvm_init_features_from_host` so that `vm_copy_id_regs` can properly\ninitialize them and set the flag once done."
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-04-13T06:07:12.019Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
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        },
        {
          "url": "https://git.kernel.org/stable/c/7e7c2cf0024d89443a7af52e09e47b1fe634ab17"
        }
      ],
      "title": "KVM: arm64: Fix ID register initialization for non-protected pKVM guests",
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    "assignerShortName": "Linux",
    "cveId": "CVE-2026-23425",
    "datePublished": "2026-04-03T13:24:33.384Z",
    "dateReserved": "2026-01-13T15:37:46.015Z",
    "dateUpdated": "2026-04-13T06:07:12.019Z",
    "state": "PUBLISHED"
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      "date": "2026-04-22",
      "epss": "0.00022",
      "percentile": "0.06037"
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    "nvd": "{\"cve\":{\"id\":\"CVE-2026-23425\",\"sourceIdentifier\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"published\":\"2026-04-03T14:16:28.747\",\"lastModified\":\"2026-04-03T16:10:23.730\",\"vulnStatus\":\"Awaiting Analysis\",\"cveTags\":[],\"descriptions\":[{\"lang\":\"en\",\"value\":\"In the Linux kernel, the following vulnerability has been resolved:\\n\\nKVM: arm64: Fix ID register initialization for non-protected pKVM guests\\n\\nIn protected mode, the hypervisor maintains a separate instance of\\nthe `kvm` structure for each VM. For non-protected VMs, this structure is\\ninitialized from the host\u0027s `kvm` state.\\n\\nCurrently, `pkvm_init_features_from_host()` copies the\\n`KVM_ARCH_FLAG_ID_REGS_INITIALIZED` flag from the host without the\\nunderlying `id_regs` data being initialized. This results in the\\nhypervisor seeing the flag as set while the ID registers remain zeroed.\\n\\nConsequently, `kvm_has_feat()` checks at EL2 fail (return 0) for\\nnon-protected VMs. This breaks logic that relies on feature detection,\\nsuch as `ctxt_has_tcrx()` for TCR2_EL1 support. As a result, certain\\nsystem registers (e.g., TCR2_EL1, PIR_EL1, POR_EL1) are not\\nsaved/restored during the world switch, which could lead to state\\ncorruption.\\n\\nFix this by explicitly copying the ID registers from the host `kvm` to\\nthe hypervisor `kvm` for non-protected VMs during initialization, since\\nwe trust the host with its non-protected guests\u0027 features. Also ensure\\n`KVM_ARCH_FLAG_ID_REGS_INITIALIZED` is cleared initially in\\n`pkvm_init_features_from_host` so that `vm_copy_id_regs` can properly\\ninitialize them and set the flag once done.\"}],\"metrics\":{},\"references\":[{\"url\":\"https://git.kernel.org/stable/c/7e7c2cf0024d89443a7af52e09e47b1fe634ab17\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/858620655c1fbff05997e162fc7d83a3293d5142\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/bce3847f7c51b86332bf2e554c9e80ca3820f16c\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"}]}}"
  }
}


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  • Confirmed: The vulnerability has been validated from an analyst's perspective.
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