Vulnerability-Lookup

GHSA-23QP-F5G5-J76H

Vulnerability from github – Published: 2026-04-03 15:30 – Updated: 2026-04-03 15:30

Details

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.

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{
  "affected": [],
  "aliases": [
    "CVE-2026-23425"
  ],
  "database_specific": {
    "cwe_ids": [],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-04-03T14:16:28Z",
    "severity": null
  },
  "details": "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.",
  "id": "GHSA-23qp-f5g5-j76h",
  "modified": "2026-04-03T15:30:31Z",
  "published": "2026-04-03T15:30:31Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-23425"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/7e7c2cf0024d89443a7af52e09e47b1fe634ab17"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/858620655c1fbff05997e162fc7d83a3293d5142"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/bce3847f7c51b86332bf2e554c9e80ca3820f16c"
    }
  ],
  "schema_version": "1.4.0",
  "severity": []
}

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

Vulnerability from cvelistv5 – Published: 2026-04-03 13:24 – Updated: 2026-04-03 13:24

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

Linux

References

URL

Tags

	https://git.kernel.org/stable/c/bce3847f7c51b8633…
	https://git.kernel.org/stable/c/858620655c1fbff05…
	https://git.kernel.org/stable/c/7e7c2cf0024d89443…

Impacted products

Vendor

Product

Version

Linux

Affected: 41d6028e28bd474298ff10409c292ec46cf43a90 , < bce3847f7c51b86332bf2e554c9e80ca3820f16c (git)
Affected: 41d6028e28bd474298ff10409c292ec46cf43a90 , < 858620655c1fbff05997e162fc7d83a3293d5142 (git)
Affected: 41d6028e28bd474298ff10409c292ec46cf43a90 , < 7e7c2cf0024d89443a7af52e09e47b1fe634ab17 (git)

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-rc2 , ≤ * (original_commit_for_fix)

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{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "arch/arm64/kvm/hyp/nvhe/pkvm.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "bce3847f7c51b86332bf2e554c9e80ca3820f16c",
              "status": "affected",
              "version": "41d6028e28bd474298ff10409c292ec46cf43a90",
              "versionType": "git"
            },
            {
              "lessThan": "858620655c1fbff05997e162fc7d83a3293d5142",
              "status": "affected",
              "version": "41d6028e28bd474298ff10409c292ec46cf43a90",
              "versionType": "git"
            },
            {
              "lessThan": "7e7c2cf0024d89443a7af52e09e47b1fe634ab17",
              "status": "affected",
              "version": "41d6028e28bd474298ff10409c292ec46cf43a90",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "arch/arm64/kvm/hyp/nvhe/pkvm.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "6.14"
            },
            {
              "lessThan": "6.14",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.17",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.19.*",
              "status": "unaffected",
              "version": "6.19.7",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.0-rc2",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.18.17",
                  "versionStartIncluding": "6.14",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.19.7",
                  "versionStartIncluding": "6.14",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.0-rc2",
                  "versionStartIncluding": "6.14",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "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."
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-04-03T13:24:33.384Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
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          "url": "https://git.kernel.org/stable/c/bce3847f7c51b86332bf2e554c9e80ca3820f16c"
        },
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          "url": "https://git.kernel.org/stable/c/858620655c1fbff05997e162fc7d83a3293d5142"
        },
        {
          "url": "https://git.kernel.org/stable/c/7e7c2cf0024d89443a7af52e09e47b1fe634ab17"
        }
      ],
      "title": "KVM: arm64: Fix ID register initialization for non-protected pKVM guests",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-23425",
    "datePublished": "2026-04-03T13:24:33.384Z",
    "dateReserved": "2026-01-13T15:37:46.015Z",
    "dateUpdated": "2026-04-03T13:24:33.384Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}

Sightings

Author	Source	Type	Date

Nomenclature

Seen: The vulnerability was mentioned, discussed, or observed by the user.
Confirmed: The vulnerability has been validated from an analyst's perspective.
Published Proof of Concept: A public proof of concept is available for this vulnerability.
Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
Not confirmed: The user expressed doubt about the validity of the vulnerability.
Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.

Detection rules are retrieved from Rulezet.

Action not permitted

GHSA-23QP-F5G5-J76H

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

Tags

Sightings

Nomenclature