CVE-2026-64106 (GCVE-0-2026-64106)
Vulnerability from cvelistv5
Published
2026-07-19 15:40
Modified
2026-08-05 12:39
Severity ?
9.0 (Critical) - CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:C/C:H/I:N/A:H
Summary
In the Linux kernel, the following vulnerability has been resolved: KVM: arm64: vgic-its: Reject restored DTE with out-of-range num_eventid_bits Userspace can restore an ITS Device Table Entry whose Size field encodes more EventID bits than the virtual ITS supports. The live MAPD path rejects that state, but vgic_its_restore_dte() accepts it and stores the out-of-range value in dev->num_eventid_bits. Reject restored DTEs with num_eventid_bits > VITS_TYPER_IDBITS before allocating the device. This mirrors the MAPD check and prevents the restored state from reaching vgic_its_restore_itt(), where the unchecked value can be converted into an oversized scan_its_table() range.
References
Impacted products
Vendor Product Version
Linux Linux Version: 57a9a117154c93539e33161dd318e6aeb8c04efa
Version: 57a9a117154c93539e33161dd318e6aeb8c04efa
Version: 57a9a117154c93539e33161dd318e6aeb8c04efa
Version: 57a9a117154c93539e33161dd318e6aeb8c04efa
Version: 57a9a117154c93539e33161dd318e6aeb8c04efa
Version: 57a9a117154c93539e33161dd318e6aeb8c04efa
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{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "arch/arm64/kvm/vgic/vgic-its.c"
          ],
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        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "arch/arm64/kvm/vgic/vgic-its.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "4.12"
            },
            {
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              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
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              "status": "unaffected",
              "version": "6.1.175",
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              "status": "unaffected",
              "version": "6.6.142",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.12.*",
              "status": "unaffected",
              "version": "6.12.92",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "6.18.*",
              "status": "unaffected",
              "version": "6.18.34",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "7.0.*",
              "status": "unaffected",
              "version": "7.0.11",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "7.1",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.1.175",
                  "versionStartIncluding": "4.12",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "6.6.142",
                  "versionStartIncluding": "4.12",
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                {
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                  "vulnerable": true
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              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nKVM: arm64: vgic-its: Reject restored DTE with out-of-range num_eventid_bits\n\nUserspace can restore an ITS Device Table Entry whose Size field encodes\nmore EventID bits than the virtual ITS supports.  The live MAPD path\nrejects that state, but vgic_its_restore_dte() accepts it and stores the\nout-of-range value in dev-\u003enum_eventid_bits.\n\nReject restored DTEs with num_eventid_bits \u003e VITS_TYPER_IDBITS before\nallocating the device.  This mirrors the MAPD check and prevents the\nrestored state from reaching vgic_its_restore_itt(), where the unchecked\nvalue can be converted into an oversized scan_its_table() range."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "baseScore": 9,
            "baseSeverity": "CRITICAL",
            "vectorString": "CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:C/C:H/I:N/A:H",
            "version": "3.1"
          },
          "scenarios": [
            {
              "lang": "en",
              "value": "AV:L - The bug is reached only through the KVM device ioctl path (KVM_SET_DEVICE_ATTR with KVM_DEV_ARM_ITS_RESTORE_TABLES), which requires a local process with access to a VM file descriptor; it is not triggered by network packets or guest MMIO/ITS commands.\nAC:L - An attacker can reliably plant a crafted Device Table Entry in guest RAM (Size field encoding 17\u201332 EventID bits) and have it processed during migration/snapshot restore; no race or attacker-uncontrollable memory layout is required, and the live MAPD path already proves the invalid state is straightforward to supply.\nPR:N - The highest-impact scenario is a malicious cloud VM tenant who needs no host privileges: they write a malformed DTE directly into guest physical memory (bypassing MAPD validation) and trigger host-side restore during automated live migration or snapshot resume, without requiring /dev/kvm or root on the host.\nUI:N - Exploitation does not require victim interaction beyond normal hypervisor operations such as automated live migration or snapshot restore that the attacker can initiate as a VM tenant; no end-user action like opening a file is needed.\nS:C - The vulnerability crosses the VM security boundary because guest-controlled saved state causes the host kernel to perform an oversized ITS table scan and mass kernel allocations, impacting host availability outside the guest\u0027s security scope.\nC:H - The unchecked num_eventid_bits value inflates scan_its_table()\u0027s range up to BIT_ULL(32)*8 bytes (and can wrap the int size parameter for values 28\u201331), causing the host kernel to read far beyond the valid ITT bounds through kvm_read_guest_lock across a large guest GPA span.\nI:N - The flaw causes excessive guest-memory reads and kernel object allocation but does not corrupt or write host kernel memory; there is no demonstrated arbitrary host write, use-after-free, or code-execution primitive from this bug alone.\nA:H - The oversized scan can loop for an enormous number of kvm_read_guest_lock iterations (worse when the truncated int size wraps to a huge unsigned length), and valid-looking restored ITEs can drive unbounded vgic_add_lpi/kzalloc allocations, exhausting host CPU and memory and causing severe denial of service."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-08-05T12:39:16.848Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/1716b7fea2ead941a0dfac06c4504a3437cdf00d"
        },
        {
          "url": "https://git.kernel.org/stable/c/dab9f93251b2c86a033de6098d0c73afddd55d4a"
        },
        {
          "url": "https://git.kernel.org/stable/c/b94538186a3eae3763b8f96dacd610920a865aa7"
        },
        {
          "url": "https://git.kernel.org/stable/c/0680f511926589206f81f57f76ce131d7741a316"
        },
        {
          "url": "https://git.kernel.org/stable/c/8bcd15b690a390241179516af1b6ae49ebfd9d95"
        },
        {
          "url": "https://git.kernel.org/stable/c/9ce754ed8e7ab4e3999767ce1505f85c449ccb07"
        }
      ],
      "title": "KVM: arm64: vgic-its: Reject restored DTE with out-of-range num_eventid_bits",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-64106",
    "datePublished": "2026-07-19T15:40:09.344Z",
    "dateReserved": "2026-07-19T07:54:57.034Z",
    "dateUpdated": "2026-08-05T12:39:16.848Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}


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