CVE-2021-47255 (GCVE-0-2021-47255)

Vulnerability from cvelistv5 – Published: 2024-05-21 14:19 – Updated: 2026-05-11 13:50
VLAI
Title
kvm: LAPIC: Restore guard to prevent illegal APIC register access
Summary
In the Linux kernel, the following vulnerability has been resolved: kvm: LAPIC: Restore guard to prevent illegal APIC register access Per the SDM, "any access that touches bytes 4 through 15 of an APIC register may cause undefined behavior and must not be executed." Worse, such an access in kvm_lapic_reg_read can result in a leak of kernel stack contents. Prior to commit 01402cf81051 ("kvm: LAPIC: write down valid APIC registers"), such an access was explicitly disallowed. Restore the guard that was removed in that commit.
Severity
No CVSS data available.
SSVC
Exploitation: none Automatable: no Technical Impact: partial
CISA Coordinator · CISA-ADP (v2.0.3)
Decision recorded 2024-05-21 18:50 UTC
Assigner
Linux CNA under the mitre root
CNA scorecard D 53/100 over 7033 records in the last 180 days details
References
Impacted products
Vendor Product Version CPE status
Linux Linux Affected: 01402cf81051f796dac7c60ca11d6147153ca46a , < bf99ea52970caeb4583bdba1192c1f9b53b12c84 (git)
Affected: 01402cf81051f796dac7c60ca11d6147153ca46a , < 018685461a5b9a9a70e664ac77aef0d7415a3fd5 (git)
Affected: 01402cf81051f796dac7c60ca11d6147153ca46a , < a2aff09807fbe4018c269d3773a629949058b210 (git)
Affected: 01402cf81051f796dac7c60ca11d6147153ca46a , < 218bf772bddd221489c38dde6ef8e917131161f6 (git)
guessed Create a notification for this product.
Linux Linux Affected: 5.3
Unaffected: 0 , < 5.3 (semver)
Unaffected: 5.4.128 , ≤ 5.4.* (semver)
Unaffected: 5.10.46 , ≤ 5.10.* (semver)
Unaffected: 5.12.13 , ≤ 5.12.* (semver)
Unaffected: 5.13 , ≤ * (original_commit_for_fix)
guessed Create a notification for this product.
Show details on NVD website
To clipboard 

{
  "containers": {
    "adp": [
      {
        "metrics": [
          {
            "other": {
              "content": {
                "id": "CVE-2021-47255",
                "options": [
                  {
                    "Exploitation": "none"
                  },
                  {
                    "Automatable": "no"
                  },
                  {
                    "Technical Impact": "partial"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2024-05-21T18:50:43.929512Z",
                "version": "2.0.3"
              },
              "type": "ssvc"
            }
          }
        ],
        "providerMetadata": {
          "dateUpdated": "2024-06-04T17:14:17.935Z",
          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
        },
        "title": "CISA ADP Vulnrichment"
      },
      {
        "providerMetadata": {
          "dateUpdated": "2024-08-04T05:32:07.995Z",
          "orgId": "af854a3a-2127-422b-91ae-364da2661108",
          "shortName": "CVE"
        },
        "references": [
          {
            "tags": [
              "x_transferred"
            ],
            "url": "https://git.kernel.org/stable/c/bf99ea52970caeb4583bdba1192c1f9b53b12c84"
          },
          {
            "tags": [
              "x_transferred"
            ],
            "url": "https://git.kernel.org/stable/c/018685461a5b9a9a70e664ac77aef0d7415a3fd5"
          },
          {
            "tags": [
              "x_transferred"
            ],
            "url": "https://git.kernel.org/stable/c/a2aff09807fbe4018c269d3773a629949058b210"
          },
          {
            "tags": [
              "x_transferred"
            ],
            "url": "https://git.kernel.org/stable/c/218bf772bddd221489c38dde6ef8e917131161f6"
          }
        ],
        "title": "CVE Program Container"
      }
    ],
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "arch/x86/kvm/lapic.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "lessThan": "bf99ea52970caeb4583bdba1192c1f9b53b12c84",
              "status": "affected",
              "version": "01402cf81051f796dac7c60ca11d6147153ca46a",
              "versionType": "git"
            },
            {
              "lessThan": "018685461a5b9a9a70e664ac77aef0d7415a3fd5",
              "status": "affected",
              "version": "01402cf81051f796dac7c60ca11d6147153ca46a",
              "versionType": "git"
            },
            {
              "lessThan": "a2aff09807fbe4018c269d3773a629949058b210",
              "status": "affected",
              "version": "01402cf81051f796dac7c60ca11d6147153ca46a",
              "versionType": "git"
            },
            {
              "lessThan": "218bf772bddd221489c38dde6ef8e917131161f6",
              "status": "affected",
              "version": "01402cf81051f796dac7c60ca11d6147153ca46a",
              "versionType": "git"
            }
          ]
        },
        {
          "defaultStatus": "affected",
          "product": "Linux",
          "programFiles": [
            "arch/x86/kvm/lapic.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "5.3"
            },
            {
              "lessThan": "5.3",
              "status": "unaffected",
              "version": "0",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "5.4.*",
              "status": "unaffected",
              "version": "5.4.128",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "5.10.*",
              "status": "unaffected",
              "version": "5.10.46",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "5.12.*",
              "status": "unaffected",
              "version": "5.12.13",
              "versionType": "semver"
            },
            {
              "lessThanOrEqual": "*",
              "status": "unaffected",
              "version": "5.13",
              "versionType": "original_commit_for_fix"
            }
          ]
        }
      ],
      "cpeApplicability": [
        {
          "nodes": [
            {
              "cpeMatch": [
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "5.4.128",
                  "versionStartIncluding": "5.3",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "5.10.46",
                  "versionStartIncluding": "5.3",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "5.12.13",
                  "versionStartIncluding": "5.3",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "5.13",
                  "versionStartIncluding": "5.3",
                  "vulnerable": true
                }
              ],
              "negate": false,
              "operator": "OR"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nkvm: LAPIC: Restore guard to prevent illegal APIC register access\n\nPer the SDM, \"any access that touches bytes 4 through 15 of an APIC\nregister may cause undefined behavior and must not be executed.\"\nWorse, such an access in kvm_lapic_reg_read can result in a leak of\nkernel stack contents. Prior to commit 01402cf81051 (\"kvm: LAPIC:\nwrite down valid APIC registers\"), such an access was explicitly\ndisallowed. Restore the guard that was removed in that commit."
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-05-11T13:50:57.669Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/bf99ea52970caeb4583bdba1192c1f9b53b12c84"
        },
        {
          "url": "https://git.kernel.org/stable/c/018685461a5b9a9a70e664ac77aef0d7415a3fd5"
        },
        {
          "url": "https://git.kernel.org/stable/c/a2aff09807fbe4018c269d3773a629949058b210"
        },
        {
          "url": "https://git.kernel.org/stable/c/218bf772bddd221489c38dde6ef8e917131161f6"
        }
      ],
      "title": "kvm: LAPIC: Restore guard to prevent illegal APIC register access",
      "x_generator": {
        "engine": "bippy-1.2.0"
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2021-47255",
    "datePublished": "2024-05-21T14:19:50.125Z",
    "dateReserved": "2024-04-10T18:59:19.539Z",
    "dateUpdated": "2026-05-11T13:50:57.669Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2",
  "vulnerability-lookup:meta": {
    "epss": {
      "cve": "CVE-2021-47255",
      "date": "2026-10-30",
      "epss": "0.00244",
      "percentile": "0.15657"
    },
    "nvd": {
      "cve": {
        "affected": [
          {
            "affectedData": [
              {
                "defaultStatus": "unaffected",
                "product": "Linux",
                "programFiles": [
                  "arch/x86/kvm/lapic.c"
                ],
                "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
                "vendor": "Linux",
                "versions": [
                  {
                    "lessThan": "bf99ea52970caeb4583bdba1192c1f9b53b12c84",
                    "status": "affected",
                    "version": "01402cf81051f796dac7c60ca11d6147153ca46a",
                    "versionType": "git"
                  },
                  {
                    "lessThan": "018685461a5b9a9a70e664ac77aef0d7415a3fd5",
                    "status": "affected",
                    "version": "01402cf81051f796dac7c60ca11d6147153ca46a",
                    "versionType": "git"
                  },
                  {
                    "lessThan": "a2aff09807fbe4018c269d3773a629949058b210",
                    "status": "affected",
                    "version": "01402cf81051f796dac7c60ca11d6147153ca46a",
                    "versionType": "git"
                  },
                  {
                    "lessThan": "218bf772bddd221489c38dde6ef8e917131161f6",
                    "status": "affected",
                    "version": "01402cf81051f796dac7c60ca11d6147153ca46a",
                    "versionType": "git"
                  }
                ]
              },
              {
                "defaultStatus": "affected",
                "product": "Linux",
                "programFiles": [
                  "arch/x86/kvm/lapic.c"
                ],
                "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
                "vendor": "Linux",
                "versions": [
                  {
                    "status": "affected",
                    "version": "5.3"
                  },
                  {
                    "lessThan": "5.3",
                    "status": "unaffected",
                    "version": "0",
                    "versionType": "semver"
                  },
                  {
                    "lessThanOrEqual": "5.4.*",
                    "status": "unaffected",
                    "version": "5.4.128",
                    "versionType": "semver"
                  },
                  {
                    "lessThanOrEqual": "5.10.*",
                    "status": "unaffected",
                    "version": "5.10.46",
                    "versionType": "semver"
                  },
                  {
                    "lessThanOrEqual": "5.12.*",
                    "status": "unaffected",
                    "version": "5.12.13",
                    "versionType": "semver"
                  },
                  {
                    "lessThanOrEqual": "*",
                    "status": "unaffected",
                    "version": "5.13",
                    "versionType": "original_commit_for_fix"
                  }
                ]
              }
            ],
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
          }
        ],
        "configurations": [
          {
            "nodes": [
              {
                "cpeMatch": [
                  {
                    "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                    "matchCriteriaId": "DC847EC3-F5C9-4A5D-B3AE-048BFB665C62",
                    "versionEndExcluding": "5.4.128",
                    "versionStartIncluding": "5.3",
                    "vulnerable": true
                  },
                  {
                    "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                    "matchCriteriaId": "59455D13-A902-42E1-97F7-5ED579777193",
                    "versionEndExcluding": "5.10.46",
                    "versionStartIncluding": "5.5",
                    "vulnerable": true
                  },
                  {
                    "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                    "matchCriteriaId": "7806E7E5-6D4F-4E18-81C1-79B3C60EE855",
                    "versionEndExcluding": "5.12.13",
                    "versionStartIncluding": "5.11",
                    "vulnerable": true
                  },
                  {
                    "criteria": "cpe:2.3:o:linux:linux_kernel:5.13:rc1:*:*:*:*:*:*",
                    "matchCriteriaId": "0CBAD0FC-C281-4666-AB2F-F8E6E1165DF7",
                    "vulnerable": true
                  },
                  {
                    "criteria": "cpe:2.3:o:linux:linux_kernel:5.13:rc2:*:*:*:*:*:*",
                    "matchCriteriaId": "96AC23B2-D46A-49D9-8203-8E1BEDCA8532",
                    "vulnerable": true
                  },
                  {
                    "criteria": "cpe:2.3:o:linux:linux_kernel:5.13:rc3:*:*:*:*:*:*",
                    "matchCriteriaId": "DA610E30-717C-4700-9F77-A3C9244F3BFD",
                    "vulnerable": true
                  },
                  {
                    "criteria": "cpe:2.3:o:linux:linux_kernel:5.13:rc4:*:*:*:*:*:*",
                    "matchCriteriaId": "1ECD33F5-85BE-430B-8F86-8D7BD560311D",
                    "vulnerable": true
                  },
                  {
                    "criteria": "cpe:2.3:o:linux:linux_kernel:5.13:rc5:*:*:*:*:*:*",
                    "matchCriteriaId": "CF351855-2437-4CF5-AD7C-BDFA51F27683",
                    "vulnerable": true
                  },
                  {
                    "criteria": "cpe:2.3:o:linux:linux_kernel:5.13:rc6:*:*:*:*:*:*",
                    "matchCriteriaId": "25A855BA-2118-44F2-90EF-EBBB12AF51EF",
                    "vulnerable": true
                  }
                ],
                "negate": false,
                "operator": "OR"
              }
            ]
          }
        ],
        "cveTags": [],
        "descriptions": [
          {
            "lang": "en",
            "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nkvm: LAPIC: Restore guard to prevent illegal APIC register access\n\nPer the SDM, \"any access that touches bytes 4 through 15 of an APIC\nregister may cause undefined behavior and must not be executed.\"\nWorse, such an access in kvm_lapic_reg_read can result in a leak of\nkernel stack contents. Prior to commit 01402cf81051 (\"kvm: LAPIC:\nwrite down valid APIC registers\"), such an access was explicitly\ndisallowed. Restore the guard that was removed in that commit."
          },
          {
            "lang": "es",
            "value": "En el kernel de Linux, se ha resuelto la siguiente vulnerabilidad: kvm: LAPIC: Restaurar protecci\u00f3n para evitar el acceso ilegal al registro APIC. Seg\u00fan el SDM, \"cualquier acceso que toque los bytes 4 al 15 de un registro APIC puede causar un comportamiento indefinido y no debe ejecutarse \". Peor a\u00fan, dicho acceso en kvm_lapic_reg_read puede resultar en una fuga del contenido de la pila del kernel. Antes de confirmar 01402cf81051 (\"kvm: LAPIC: anotar registros APIC v\u00e1lidos\"), dicho acceso se prohib\u00eda expl\u00edcitamente. Restaura la guardia que se elimin\u00f3 en esa confirmaci\u00f3n."
          }
        ],
        "id": "CVE-2021-47255",
        "lastModified": "2026-06-17T04:17:01.567",
        "metrics": {
          "cvssMetricV31": [
            {
              "cvssData": {
                "attackComplexity": "LOW",
                "attackVector": "LOCAL",
                "availabilityImpact": "HIGH",
                "baseScore": 7.1,
                "baseSeverity": "HIGH",
                "confidentialityImpact": "HIGH",
                "integrityImpact": "NONE",
                "privilegesRequired": "LOW",
                "scope": "UNCHANGED",
                "userInteraction": "NONE",
                "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H",
                "version": "3.1"
              },
              "exploitabilityScore": 1.8,
              "impactScore": 5.2,
              "source": "nvd@nist.gov",
              "type": "Primary"
            }
          ],
          "ssvcV203": [
            {
              "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
              "ssvcData": {
                "id": "CVE-2021-47255",
                "options": [
                  {
                    "exploitation": "none"
                  },
                  {
                    "automatable": "no"
                  },
                  {
                    "technicalImpact": "partial"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2024-05-21T18:50:43.929512Z",
                "version": "2.0.3"
              }
            }
          ]
        },
        "published": "2024-05-21T15:15:14.303",
        "references": [
          {
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
            "tags": [
              "Patch"
            ],
            "url": "https://git.kernel.org/stable/c/018685461a5b9a9a70e664ac77aef0d7415a3fd5"
          },
          {
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
            "tags": [
              "Patch"
            ],
            "url": "https://git.kernel.org/stable/c/218bf772bddd221489c38dde6ef8e917131161f6"
          },
          {
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
            "tags": [
              "Patch"
            ],
            "url": "https://git.kernel.org/stable/c/a2aff09807fbe4018c269d3773a629949058b210"
          },
          {
            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
            "tags": [
              "Patch"
            ],
            "url": "https://git.kernel.org/stable/c/bf99ea52970caeb4583bdba1192c1f9b53b12c84"
          },
          {
            "source": "af854a3a-2127-422b-91ae-364da2661108",
            "tags": [
              "Patch"
            ],
            "url": "https://git.kernel.org/stable/c/018685461a5b9a9a70e664ac77aef0d7415a3fd5"
          },
          {
            "source": "af854a3a-2127-422b-91ae-364da2661108",
            "tags": [
              "Patch"
            ],
            "url": "https://git.kernel.org/stable/c/218bf772bddd221489c38dde6ef8e917131161f6"
          },
          {
            "source": "af854a3a-2127-422b-91ae-364da2661108",
            "tags": [
              "Patch"
            ],
            "url": "https://git.kernel.org/stable/c/a2aff09807fbe4018c269d3773a629949058b210"
          },
          {
            "source": "af854a3a-2127-422b-91ae-364da2661108",
            "tags": [
              "Patch"
            ],
            "url": "https://git.kernel.org/stable/c/bf99ea52970caeb4583bdba1192c1f9b53b12c84"
          }
        ],
        "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "vulnStatus": "Analyzed",
        "weaknesses": [
          {
            "description": [
              {
                "lang": "en",
                "value": "NVD-CWE-Other"
              }
            ],
            "source": "nvd@nist.gov",
            "type": "Primary"
          }
        ]
      }
    },
    "redhat_vex": {
      "aggregate_severity": "Low",
      "current_release_date": "2025-11-21T11:51:33+00:00",
      "cve": "CVE-2021-47255",
      "id": "CVE-2021-47255",
      "initial_release_date": "2021-01-01T00:00:00+00:00",
      "product_status:known_affected": "90",
      "product_status:known_not_affected": "108",
      "source": "Red Hat CSAF VEX",
      "status": "final",
      "title": "kernel: kvm: LAPIC: Restore guard to prevent illegal APIC register access",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2021/cve-2021-47255.json",
      "version": "3"
    },
    "vulnrichment": {
      "containers": {
        "adp": [
          {
            "providerMetadata": {
              "dateUpdated": "2024-08-04T05:32:07.995Z",
              "orgId": "af854a3a-2127-422b-91ae-364da2661108",
              "shortName": "CVE"
            },
            "references": [
              {
                "tags": [
                  "x_transferred"
                ],
                "url": "https://git.kernel.org/stable/c/bf99ea52970caeb4583bdba1192c1f9b53b12c84"
              },
              {
                "tags": [
                  "x_transferred"
                ],
                "url": "https://git.kernel.org/stable/c/018685461a5b9a9a70e664ac77aef0d7415a3fd5"
              },
              {
                "tags": [
                  "x_transferred"
                ],
                "url": "https://git.kernel.org/stable/c/a2aff09807fbe4018c269d3773a629949058b210"
              },
              {
                "tags": [
                  "x_transferred"
                ],
                "url": "https://git.kernel.org/stable/c/218bf772bddd221489c38dde6ef8e917131161f6"
              }
            ],
            "title": "CVE Program Container"
          },
          {
            "metrics": [
              {
                "other": {
                  "content": {
                    "id": "CVE-2021-47255",
                    "options": [
                      {
                        "Exploitation": "none"
                      },
                      {
                        "Automatable": "no"
                      },
                      {
                        "Technical Impact": "partial"
                      }
                    ],
                    "role": "CISA Coordinator",
                    "timestamp": "2024-05-21T18:50:43.929512Z",
                    "version": "2.0.3"
                  },
                  "type": "ssvc"
                }
              }
            ],
            "providerMetadata": {
              "dateUpdated": "2024-05-23T19:01:25.513Z",
              "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
              "shortName": "CISA-ADP"
            },
            "title": "CISA ADP Vulnrichment"
          }
        ],
        "cna": {
          "affected": [
            {
              "defaultStatus": "unaffected",
              "product": "Linux",
              "programFiles": [
                "arch/x86/kvm/lapic.c"
              ],
              "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
              "vendor": "Linux",
              "versions": [
                {
                  "lessThan": "bf99ea52970caeb4583bdba1192c1f9b53b12c84",
                  "status": "affected",
                  "version": "01402cf81051f796dac7c60ca11d6147153ca46a",
                  "versionType": "git"
                },
                {
                  "lessThan": "018685461a5b9a9a70e664ac77aef0d7415a3fd5",
                  "status": "affected",
                  "version": "01402cf81051f796dac7c60ca11d6147153ca46a",
                  "versionType": "git"
                },
                {
                  "lessThan": "a2aff09807fbe4018c269d3773a629949058b210",
                  "status": "affected",
                  "version": "01402cf81051f796dac7c60ca11d6147153ca46a",
                  "versionType": "git"
                },
                {
                  "lessThan": "218bf772bddd221489c38dde6ef8e917131161f6",
                  "status": "affected",
                  "version": "01402cf81051f796dac7c60ca11d6147153ca46a",
                  "versionType": "git"
                }
              ]
            },
            {
              "defaultStatus": "affected",
              "product": "Linux",
              "programFiles": [
                "arch/x86/kvm/lapic.c"
              ],
              "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
              "vendor": "Linux",
              "versions": [
                {
                  "status": "affected",
                  "version": "5.3"
                },
                {
                  "lessThan": "5.3",
                  "status": "unaffected",
                  "version": "0",
                  "versionType": "semver"
                },
                {
                  "lessThanOrEqual": "5.4.*",
                  "status": "unaffected",
                  "version": "5.4.128",
                  "versionType": "semver"
                },
                {
                  "lessThanOrEqual": "5.10.*",
                  "status": "unaffected",
                  "version": "5.10.46",
                  "versionType": "semver"
                },
                {
                  "lessThanOrEqual": "5.12.*",
                  "status": "unaffected",
                  "version": "5.12.13",
                  "versionType": "semver"
                },
                {
                  "lessThanOrEqual": "*",
                  "status": "unaffected",
                  "version": "5.13",
                  "versionType": "original_commit_for_fix"
                }
              ]
            }
          ],
          "cpeApplicability": [
            {
              "nodes": [
                {
                  "cpeMatch": [
                    {
                      "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                      "versionEndExcluding": "5.4.128",
                      "versionStartIncluding": "5.3",
                      "vulnerable": true
                    },
                    {
                      "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                      "versionEndExcluding": "5.10.46",
                      "versionStartIncluding": "5.3",
                      "vulnerable": true
                    },
                    {
                      "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                      "versionEndExcluding": "5.12.13",
                      "versionStartIncluding": "5.3",
                      "vulnerable": true
                    },
                    {
                      "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                      "versionEndExcluding": "5.13",
                      "versionStartIncluding": "5.3",
                      "vulnerable": true
                    }
                  ],
                  "negate": false,
                  "operator": "OR"
                }
              ]
            }
          ],
          "descriptions": [
            {
              "lang": "en",
              "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nkvm: LAPIC: Restore guard to prevent illegal APIC register access\n\nPer the SDM, \"any access that touches bytes 4 through 15 of an APIC\nregister may cause undefined behavior and must not be executed.\"\nWorse, such an access in kvm_lapic_reg_read can result in a leak of\nkernel stack contents. Prior to commit 01402cf81051 (\"kvm: LAPIC:\nwrite down valid APIC registers\"), such an access was explicitly\ndisallowed. Restore the guard that was removed in that commit."
            }
          ],
          "providerMetadata": {
            "dateUpdated": "2025-05-04T07:07:14.476Z",
            "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
            "shortName": "Linux"
          },
          "references": [
            {
              "url": "https://git.kernel.org/stable/c/bf99ea52970caeb4583bdba1192c1f9b53b12c84"
            },
            {
              "url": "https://git.kernel.org/stable/c/018685461a5b9a9a70e664ac77aef0d7415a3fd5"
            },
            {
              "url": "https://git.kernel.org/stable/c/a2aff09807fbe4018c269d3773a629949058b210"
            },
            {
              "url": "https://git.kernel.org/stable/c/218bf772bddd221489c38dde6ef8e917131161f6"
            }
          ],
          "title": "kvm: LAPIC: Restore guard to prevent illegal APIC register access",
          "x_generator": {
            "engine": "bippy-1.2.0"
          }
        }
      },
      "cveMetadata": {
        "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "assignerShortName": "Linux",
        "cveId": "CVE-2021-47255",
        "datePublished": "2024-05-21T14:19:50.125Z",
        "dateReserved": "2024-04-10T18:59:19.539Z",
        "dateUpdated": "2025-05-04T07:07:14.476Z",
        "state": "PUBLISHED"
      },
      "dataType": "CVE_RECORD",
      "dataVersion": "5.1"
    }
  }
}



Log in or create an account to share your comment.




Tags
Taxonomy of the tags.




Drag nodes to arrange them. Double-click a related vulnerability to open it, or a source to visit its link. The Physics button on the left tunes the layout and the simulation; the legend at the bottom left hides or shows nodes by kind and by sighting type.

Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

Sightings

Author Source Type Date Other

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.
Vulnerability timeline

Sightings and recorded dates, grouped by day · UTC

JSON

Loading timeline…




    Related by attack behaviour

    Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.