Vulnerability-Lookup

FKIE_CVE-2021-47390

Vulnerability from fkie_nvd - Published: 2024-05-21 15:15 - Updated: 2026-08-04 10:17

Severity

8.8 (High) - CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H
7.1 (High) - CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H

Summary

In the Linux kernel, the following vulnerability has been resolved: KVM: x86: Fix stack-out-of-bounds memory access from ioapic_write_indirect() KASAN reports the following issue: BUG: KASAN: stack-out-of-bounds in kvm_make_vcpus_request_mask+0x174/0x440 [kvm] Read of size 8 at addr ffffc9001364f638 by task qemu-kvm/4798 CPU: 0 PID: 4798 Comm: qemu-kvm Tainted: G X --------- --- Hardware name: AMD Corporation DAYTONA_X/DAYTONA_X, BIOS RYM0081C 07/13/2020 Call Trace: dump_stack+0xa5/0xe6 print_address_description.constprop.0+0x18/0x130 ? kvm_make_vcpus_request_mask+0x174/0x440 [kvm] __kasan_report.cold+0x7f/0x114 ? kvm_make_vcpus_request_mask+0x174/0x440 [kvm] kasan_report+0x38/0x50 kasan_check_range+0xf5/0x1d0 kvm_make_vcpus_request_mask+0x174/0x440 [kvm] kvm_make_scan_ioapic_request_mask+0x84/0xc0 [kvm] ? kvm_arch_exit+0x110/0x110 [kvm] ? sched_clock+0x5/0x10 ioapic_write_indirect+0x59f/0x9e0 [kvm] ? static_obj+0xc0/0xc0 ? __lock_acquired+0x1d2/0x8c0 ? kvm_ioapic_eoi_inject_work+0x120/0x120 [kvm] The problem appears to be that 'vcpu_bitmap' is allocated as a single long on stack and it should really be KVM_MAX_VCPUS long. We also seem to clear the lower 16 bits of it with bitmap_zero() for no particular reason (my guess would be that 'bitmap' and 'vcpu_bitmap' variables in kvm_bitmap_or_dest_vcpus() caused the confusion: while the later is indeed 16-bit long, the later should accommodate all possible vCPUs).

References

URL	Tags
416baaa9-dc9f-4396-8d5f-8c081fb06d67	https://git.kernel.org/stable/c/2f9b68f57c6278c322793a06063181deded0ad69	Patch
416baaa9-dc9f-4396-8d5f-8c081fb06d67	https://git.kernel.org/stable/c/99a9e9b80f19fc63be005a33d76211dd23114792	Patch
416baaa9-dc9f-4396-8d5f-8c081fb06d67	https://git.kernel.org/stable/c/bebabb76ad9acca8858e0371e102fb60d708e25b	Patch
af854a3a-2127-422b-91ae-364da2661108	https://git.kernel.org/stable/c/2f9b68f57c6278c322793a06063181deded0ad69	Patch
af854a3a-2127-422b-91ae-364da2661108	https://git.kernel.org/stable/c/99a9e9b80f19fc63be005a33d76211dd23114792	Patch
af854a3a-2127-422b-91ae-364da2661108	https://git.kernel.org/stable/c/bebabb76ad9acca8858e0371e102fb60d708e25b	Patch

Impacted products

Vendor	Product	Version
linux	linux_kernel	*
linux	linux_kernel	*
linux	linux_kernel	5.15
linux	linux_kernel	5.15
linux	linux_kernel	5.15

JSON

To clipboard

{
  "affected": [
    {
      "affectedData": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "arch/x86/kvm/ioapic.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
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              "versionType": "git"
            }
          ]
        },
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          "product": "Linux",
          "programFiles": [
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          ],
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              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
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              "status": "unaffected",
              "version": "5.10.71",
              "versionType": "semver"
            },
            {
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              "status": "unaffected",
              "version": "5.14.10",
              "versionType": "semver"
            },
            {
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              "status": "unaffected",
              "version": "5.15",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    }
  ],
  "configurations": [
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              "versionStartIncluding": "5.5",
              "vulnerable": true
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        }
      ]
    }
  ],
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nKVM: x86: Fix stack-out-of-bounds memory access from ioapic_write_indirect()\n\nKASAN reports the following issue:\n\n BUG: KASAN: stack-out-of-bounds in kvm_make_vcpus_request_mask+0x174/0x440 [kvm]\n Read of size 8 at addr ffffc9001364f638 by task qemu-kvm/4798\n\n CPU: 0 PID: 4798 Comm: qemu-kvm Tainted: G               X --------- ---\n Hardware name: AMD Corporation DAYTONA_X/DAYTONA_X, BIOS RYM0081C 07/13/2020\n Call Trace:\n  dump_stack+0xa5/0xe6\n  print_address_description.constprop.0+0x18/0x130\n  ? kvm_make_vcpus_request_mask+0x174/0x440 [kvm]\n  __kasan_report.cold+0x7f/0x114\n  ? kvm_make_vcpus_request_mask+0x174/0x440 [kvm]\n  kasan_report+0x38/0x50\n  kasan_check_range+0xf5/0x1d0\n  kvm_make_vcpus_request_mask+0x174/0x440 [kvm]\n  kvm_make_scan_ioapic_request_mask+0x84/0xc0 [kvm]\n  ? kvm_arch_exit+0x110/0x110 [kvm]\n  ? sched_clock+0x5/0x10\n  ioapic_write_indirect+0x59f/0x9e0 [kvm]\n  ? static_obj+0xc0/0xc0\n  ? __lock_acquired+0x1d2/0x8c0\n  ? kvm_ioapic_eoi_inject_work+0x120/0x120 [kvm]\n\nThe problem appears to be that \u0027vcpu_bitmap\u0027 is allocated as a single long\non stack and it should really be KVM_MAX_VCPUS long. We also seem to clear\nthe lower 16 bits of it with bitmap_zero() for no particular reason (my\nguess would be that \u0027bitmap\u0027 and \u0027vcpu_bitmap\u0027 variables in\nkvm_bitmap_or_dest_vcpus() caused the confusion: while the later is indeed\n16-bit long, the later should accommodate all possible vCPUs)."
    },
    {
      "lang": "es",
      "value": "En el kernel de Linux, se resolvi\u00f3 la siguiente vulnerabilidad: KVM: x86: corrige el acceso a la memoria de pila fuera de los l\u00edmites desde ioapic_write_indirect() KASAN informa el siguiente problema: BUG: KASAN: pila fuera de los l\u00edmites en kvm_make_vcpus_request_mask+ 0x174/0x440 [kvm] Lectura de tama\u00f1o 8 en la direcci\u00f3n ffffc9001364f638 por tarea qemu-kvm/4798 CPU: 0 PID: 4798 Comm: qemu-kvm Contaminado: GX --------- --- Nombre de hardware: AMD Corporaci\u00f3n DAYTONA_X/DAYTONA_X, BIOS RYM0081C 13/07/2020 Seguimiento de llamadas: dump_stack+0xa5/0xe6 print_address_description.constprop.0+0x18/0x130 ? kvm_make_vcpus_request_mask+0x174/0x440 [kvm] __kasan_report.cold+0x7f/0x114 ? kvm_make_vcpus_request_mask+0x174/0x440 [kvm] kasan_report+0x38/0x50 kasan_check_range+0xf5/0x1d0 kvm_make_vcpus_request_mask+0x174/0x440 [kvm] 0 [kvm] ? kvm_arch_exit+0x110/0x110 [kvm] ? sched_clock+0x5/0x10 ioapic_write_indirect+0x59f/0x9e0 [kvm] ? static_obj+0xc0/0xc0? __lock_acquired+0x1d2/0x8c0? kvm_ioapic_eoi_inject_work+0x120/0x120 [kvm] El problema parece ser que \u0027vcpu_bitmap\u0027 est\u00e1 asignado como un \u00fanico largo en la pila y en realidad deber\u00eda ser KVM_MAX_VCPUS largo. Tambi\u00e9n parece que borramos los 16 bits inferiores con bitmap_zero() sin ning\u00fan motivo en particular (supongo que las variables \u0027bitmap\u0027 y \u0027vcpu_bitmap\u0027 en kvm_bitmap_or_dest_vcpus() causaron la confusi\u00f3n: mientras que la \u00faltima tiene 16 bits de longitud , este \u00faltimo deber\u00eda acomodar todas las vCPU posibles)."
    }
  ],
  "id": "CVE-2021-47390",
  "lastModified": "2026-08-04T10:17:01.297",
  "metrics": {
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        "cvssData": {
          "attackComplexity": "LOW",
          "attackVector": "LOCAL",
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          "baseScore": 8.8,
          "baseSeverity": "HIGH",
          "confidentialityImpact": "HIGH",
          "integrityImpact": "HIGH",
          "privilegesRequired": "LOW",
          "scope": "CHANGED",
          "userInteraction": "NONE",
          "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H",
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        "type": "Secondary"
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      "type": "Primary"
    }
  ]
}

CVE-2021-47390 (GCVE-0-2021-47390)

Vulnerability from cvelistv5 – Published: 2024-05-21 15:03 – Updated: 2026-08-05 08:47

Title

KVM: x86: Fix stack-out-of-bounds memory access from ioapic_write_indirect()

Summary

Severity

8.8 (High)


                        
                          CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H

SSVC

Exploitation: none Automatable: no Technical Impact: partial

CISA Coordinator · CISA-ADP (v2.0.3)

Decision recorded 2024-06-17 17:37 UTC

Assigner

Linux CNA under the mitre root

CNA scorecard D 53/100 over 6856 records in the last 180 days details

References

3 references

URL	Tags
https://git.kernel.org/stable/c/bebabb76ad9acca88…
https://git.kernel.org/stable/c/99a9e9b80f19fc63b…
https://git.kernel.org/stable/c/2f9b68f57c6278c32…

Impacted products

2 products

Vendor	Product	Version
Linux	Linux	Affected: 7ee30bc132c683d06a6d9e360e39e483e3990708 , < bebabb76ad9acca8858e0371e102fb60d708e25b (git) Affected: 7ee30bc132c683d06a6d9e360e39e483e3990708 , < 99a9e9b80f19fc63be005a33d76211dd23114792 (git) Affected: 7ee30bc132c683d06a6d9e360e39e483e3990708 , < 2f9b68f57c6278c322793a06063181deded0ad69 (git)
Linux	Linux	Affected: 5.5 Unaffected: 0 , < 5.5 (semver) Unaffected: 5.10.71 , ≤ 5.10.* (semver) Unaffected: 5.14.10 , ≤ 5.14.* (semver) Unaffected: 5.15 , ≤ * (original_commit_for_fix)

Show details on NVD website

JSON

To clipboard

{
  "containers": {
    "adp": [
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        "metrics": [
          {
            "other": {
              "content": {
                "id": "CVE-2021-47390",
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                  },
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                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2024-06-17T17:37:17.652949Z",
                "version": "2.0.3"
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          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
        },
        "title": "CISA ADP Vulnrichment"
      },
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          "dateUpdated": "2024-08-04T05:39:59.812Z",
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        ],
        "title": "CVE Program Container"
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    "cna": {
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          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
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        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nKVM: x86: Fix stack-out-of-bounds memory access from ioapic_write_indirect()\n\nKASAN reports the following issue:\n\n BUG: KASAN: stack-out-of-bounds in kvm_make_vcpus_request_mask+0x174/0x440 [kvm]\n Read of size 8 at addr ffffc9001364f638 by task qemu-kvm/4798\n\n CPU: 0 PID: 4798 Comm: qemu-kvm Tainted: G               X --------- ---\n Hardware name: AMD Corporation DAYTONA_X/DAYTONA_X, BIOS RYM0081C 07/13/2020\n Call Trace:\n  dump_stack+0xa5/0xe6\n  print_address_description.constprop.0+0x18/0x130\n  ? kvm_make_vcpus_request_mask+0x174/0x440 [kvm]\n  __kasan_report.cold+0x7f/0x114\n  ? kvm_make_vcpus_request_mask+0x174/0x440 [kvm]\n  kasan_report+0x38/0x50\n  kasan_check_range+0xf5/0x1d0\n  kvm_make_vcpus_request_mask+0x174/0x440 [kvm]\n  kvm_make_scan_ioapic_request_mask+0x84/0xc0 [kvm]\n  ? kvm_arch_exit+0x110/0x110 [kvm]\n  ? sched_clock+0x5/0x10\n  ioapic_write_indirect+0x59f/0x9e0 [kvm]\n  ? static_obj+0xc0/0xc0\n  ? __lock_acquired+0x1d2/0x8c0\n  ? kvm_ioapic_eoi_inject_work+0x120/0x120 [kvm]\n\nThe problem appears to be that \u0027vcpu_bitmap\u0027 is allocated as a single long\non stack and it should really be KVM_MAX_VCPUS long. We also seem to clear\nthe lower 16 bits of it with bitmap_zero() for no particular reason (my\nguess would be that \u0027bitmap\u0027 and \u0027vcpu_bitmap\u0027 variables in\nkvm_bitmap_or_dest_vcpus() caused the confusion: while the later is indeed\n16-bit long, the later should accommodate all possible vCPUs)."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "baseScore": 8.8,
            "baseSeverity": "HIGH",
            "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H",
            "version": "3.1"
          },
          "scenarios": [
            {
              "lang": "en",
              "value": "AV:L - The bug is reached when a guest writes the in-kernel IOAPIC MMIO window (0xfec00000), causing a KVM MMIO exit into ioapic_mmio_write \u2192 ioapic_write_indirect on the host; this is a local hypervisor/guest interface, not a network protocol path.\nAC:L - A guest (or VMM user who creates the VM) can reliably trigger the path by writing an IOAPIC redirect entry with FIXED delivery mode; the undersized bitmap is always over-read, and with \u226565 vCPUs the attacker-controlled dest can also force out-of-bounds __set_bit writes with no race or uncontrolled condition.\nPR:L - Exploitation needs only the ability to run a KVM guest that uses the in-kernel irqchip\u2014typically an unprivileged kvm-group user on /dev/kvm, or a cloud tenant controlling their guest OS\u2014not real host root/CAP_SYS_ADMIN.\nUI:N - No victim action is required; the attacker triggers the vulnerable IOAPIC write path directly from guest code or their own VMM once the VM exists.\nS:C - A malicious guest corrupts host-kernel stack memory in KVM\u2019s IOAPIC emulation, crossing the guest/host security boundary and enabling a potential VM escape affecting the host and other tenants.\nC:H - kvm_make_vcpus_request_mask performs a stack out-of-bounds read of the undersized vcpu_bitmap across KVM_MAX_VCPUS bits (~128 bytes), and stack corruption from the related OOB write can be leveraged for further host memory disclosure.\nI:H - kvm_bitmap_or_dest_vcpus uses __set_bit() on vcpu_idx values that can exceed the single unsigned long (bits \u226564), writing past the stack allocation toward higher stack addresses and enabling host memory corruption / control-flow hijacking.\nA:H - The out-of-bounds stack access can oops/panic the host kernel (as shown by the KASAN report in qemu-kvm), so availability impact on the host is high."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-08-05T08:47:35.643Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/bebabb76ad9acca8858e0371e102fb60d708e25b"
        },
        {
          "url": "https://git.kernel.org/stable/c/99a9e9b80f19fc63be005a33d76211dd23114792"
        },
        {
          "url": "https://git.kernel.org/stable/c/2f9b68f57c6278c322793a06063181deded0ad69"
        }
      ],
      "title": "KVM: x86: Fix stack-out-of-bounds memory access from ioapic_write_indirect()",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2021-47390",
    "datePublished": "2024-05-21T15:03:48.883Z",
    "dateReserved": "2024-05-21T14:58:30.813Z",
    "dateUpdated": "2026-08-05T08:47:35.643Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}

Sightings

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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.

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