GCVE Workshop - 22 September 2026 (14:00-18:00), Luxembourg Before The Vulnopticon Conference - Registration

CVE-2021-26318 (GCVE-0-2021-26318)

Vulnerability from cvelistv5 – Published: 2021-10-13 18:29 – Updated: 2024-09-16 16:48
VLAI
Title
Side-channels Related to the x86 PREFETCH Instruction
Summary
A timing and power-based side channel attack leveraging the x86 PREFETCH instructions on some AMD CPUs could potentially result in leaked kernel address space information.
Severity
4.7 (Medium)
CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:N/A:N
CWE
  • CWE-208 - Information Exposure Through Timing Discrepancy
Assigner
References
Impacted products
Vendor Product Version CPE status
AMD All supported processors Affected: unspecified , < undefined (custom)
guessed Create a notification for this product.
Date Public
2021-10-12 00:00
Show details on NVD website
To clipboard 

{
  "containers": {
    "adp": [
      {
        "providerMetadata": {
          "dateUpdated": "2024-08-03T20:19:20.137Z",
          "orgId": "af854a3a-2127-422b-91ae-364da2661108",
          "shortName": "CVE"
        },
        "references": [
          {
            "tags": [
              "x_refsource_MISC",
              "x_transferred"
            ],
            "url": "https://www.amd.com/en/corporate/product-security/bulletin/amd-sb-1017"
          }
        ],
        "title": "CVE Program Container"
      }
    ],
    "cna": {
      "affected": [
        {
          "product": "All supported processors",
          "vendor": "AMD",
          "versions": [
            {
              "lessThan": "undefined",
              "status": "affected",
              "version": "unspecified",
              "versionType": "custom"
            }
          ]
        }
      ],
      "datePublic": "2021-10-12T00:00:00.000Z",
      "descriptions": [
        {
          "lang": "en",
          "value": "A timing and power-based side channel attack leveraging the x86 PREFETCH instructions on some AMD CPUs could potentially result in leaked kernel address space information."
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "cweId": "CWE-208",
              "description": "CWE-208 Information Exposure Through Timing Discrepancy",
              "lang": "en",
              "type": "CWE"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2021-10-13T18:29:14.000Z",
        "orgId": "b58fc414-a1e4-4f92-9d70-1add41838648",
        "shortName": "AMD"
      },
      "references": [
        {
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://www.amd.com/en/corporate/product-security/bulletin/amd-sb-1017"
        }
      ],
      "source": {
        "advisory": "AMD-SB-1017",
        "discovery": "EXTERNAL"
      },
      "title": "Side-channels Related to the x86 PREFETCH Instruction",
      "x_generator": {
        "engine": "Vulnogram 0.0.9"
      },
      "x_legacyV4Record": {
        "CVE_data_meta": {
          "ASSIGNER": "psirt@amd.com",
          "DATE_PUBLIC": "2021-10-12T19:30:00.000Z",
          "ID": "CVE-2021-26318",
          "STATE": "PUBLIC",
          "TITLE": "Side-channels Related to the x86 PREFETCH Instruction"
        },
        "affects": {
          "vendor": {
            "vendor_data": [
              {
                "product": {
                  "product_data": [
                    {
                      "product_name": "All supported processors",
                      "version": {
                        "version_data": [
                          {
                            "version_affected": "\u003c",
                            "version_value": ""
                          }
                        ]
                      }
                    }
                  ]
                },
                "vendor_name": "AMD"
              }
            ]
          }
        },
        "data_format": "MITRE",
        "data_type": "CVE",
        "data_version": "4.0",
        "description": {
          "description_data": [
            {
              "lang": "eng",
              "value": "A timing and power-based side channel attack leveraging the x86 PREFETCH instructions on some AMD CPUs could potentially result in leaked kernel address space information."
            }
          ]
        },
        "generator": {
          "engine": "Vulnogram 0.0.9"
        },
        "problemtype": {
          "problemtype_data": [
            {
              "description": [
                {
                  "lang": "eng",
                  "value": "CWE-208 Information Exposure Through Timing Discrepancy"
                }
              ]
            }
          ]
        },
        "references": {
          "reference_data": [
            {
              "name": "https://www.amd.com/en/corporate/product-security/bulletin/amd-sb-1017",
              "refsource": "MISC",
              "url": "https://www.amd.com/en/corporate/product-security/bulletin/amd-sb-1017"
            }
          ]
        },
        "source": {
          "advisory": "AMD-SB-1017",
          "discovery": "EXTERNAL"
        }
      }
    }
  },
  "cveMetadata": {
    "assignerOrgId": "b58fc414-a1e4-4f92-9d70-1add41838648",
    "assignerShortName": "AMD",
    "cveId": "CVE-2021-26318",
    "datePublished": "2021-10-13T18:29:14.977Z",
    "dateReserved": "2021-01-29T00:00:00.000Z",
    "dateUpdated": "2024-09-16T16:48:55.696Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.1",
  "vulnerability-lookup:meta": {
    "epss": {
      "cve": "CVE-2021-26318",
      "date": "2026-09-16",
      "epss": "0.00327",
      "percentile": "0.25831"
    },
    "fkie_nvd": {
      "configurations": "[{\"operator\": \"AND\", \"nodes\": [{\"operator\": \"OR\", \"negate\": false, \"cpeMatch\": [{\"vulnerable\": true, \"criteria\": \"cpe:2.3:o:amd:athlon_firmware:-:*:*:*:*:*:*:*\", \"matchCriteriaId\": \"ED9F64FB-2B5D-4B9B-9ABD-23324005CB38\"}]}, {\"operator\": \"OR\", \"negate\": false, \"cpeMatch\": [{\"vulnerable\": false, \"criteria\": \"cpe:2.3:h:amd:athlon:-:*:*:*:*:*:*:*\", \"matchCriteriaId\": \"2C0A97A7-4790-4234-9617-B88A96C2C2F7\"}]}]}, {\"operator\": \"AND\", \"nodes\": [{\"operator\": \"OR\", \"negate\": false, \"cpeMatch\": [{\"vulnerable\": true, \"criteria\": \"cpe:2.3:o:amd:athlon_pro_firmware:-:*:*:*:*:*:*:*\", \"matchCriteriaId\": \"4CDE494B-7C70-4359-856B-793AF93FECE1\"}]}, {\"operator\": \"OR\", \"negate\": false, \"cpeMatch\": [{\"vulnerable\": false, \"criteria\": \"cpe:2.3:h:amd:athlon_pro:-:*:*:*:*:*:*:*\", \"matchCriteriaId\": \"464AD06F-B6C1-4F2C-B649-DFA1AE387DD8\"}]}]}, {\"operator\": \"AND\", \"nodes\": [{\"operator\": \"OR\", \"negate\": false, \"cpeMatch\": [{\"vulnerable\": true, \"criteria\": \"cpe:2.3:o:amd:epyc_firmware:-:*:*:*:*:*:*:*\", \"matchCriteriaId\": \"33B3CD35-6644-42BD-84C8-D7584178C50E\"}]}, {\"operator\": \"OR\", \"negate\": false, \"cpeMatch\": [{\"vulnerable\": false, \"criteria\": \"cpe:2.3:h:amd:epyc:-:*:*:*:*:*:*:*\", \"matchCriteriaId\": \"CF7F2DBC-56AD-4D96-AFB3-5F97FACABDC1\"}]}]}, {\"operator\": \"AND\", \"nodes\": [{\"operator\": \"OR\", \"negate\": false, \"cpeMatch\": [{\"vulnerable\": true, \"criteria\": \"cpe:2.3:o:amd:ryzen_firmware:-:*:*:*:*:*:*:*\", \"matchCriteriaId\": \"CAEA5209-C0F6-4645-A541-A68CBC70695B\"}]}, {\"operator\": \"OR\", \"negate\": false, \"cpeMatch\": [{\"vulnerable\": false, \"criteria\": \"cpe:2.3:h:amd:ryzen:-:*:*:*:*:*:*:*\", \"matchCriteriaId\": \"047F0F4D-DCE1-4E3F-A888-39E894DF857D\"}]}]}, {\"operator\": \"AND\", \"nodes\": [{\"operator\": \"OR\", \"negate\": false, \"cpeMatch\": [{\"vulnerable\": true, \"criteria\": \"cpe:2.3:o:amd:ryzen_pro_firmware:-:*:*:*:*:*:*:*\", \"matchCriteriaId\": \"08E59D0B-FB2F-4C17-B9BC-462DFB366777\"}]}, {\"operator\": \"OR\", \"negate\": false, \"cpeMatch\": [{\"vulnerable\": false, \"criteria\": \"cpe:2.3:h:amd:ryzen_pro:-:*:*:*:*:*:*:*\", \"matchCriteriaId\": \"BA9541F0-5B33-4F09-B201-E887DA572571\"}]}]}]",
      "descriptions": "[{\"lang\": \"en\", \"value\": \"A timing and power-based side channel attack leveraging the x86 PREFETCH instructions on some AMD CPUs could potentially result in leaked kernel address space information.\"}, {\"lang\": \"es\", \"value\": \"Un ataque de canal lateral basado en el tiempo y la energ\\u00eda aprovechando las instrucciones x86 PREFETCH en algunas CPUs de AMD podr\\u00eda potencialmente resultar en una filtraci\\u00f3n de informaci\\u00f3n del espacio de direcciones del kernel\"}]",
      "id": "CVE-2021-26318",
      "lastModified": "2024-11-21T05:56:05.303",
      "metrics": "{\"cvssMetricV31\": [{\"source\": \"nvd@nist.gov\", \"type\": \"Primary\", \"cvssData\": {\"version\": \"3.1\", \"vectorString\": \"CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:N/A:N\", \"baseScore\": 4.7, \"baseSeverity\": \"MEDIUM\", \"attackVector\": \"LOCAL\", \"attackComplexity\": \"HIGH\", \"privilegesRequired\": \"LOW\", \"userInteraction\": \"NONE\", \"scope\": \"UNCHANGED\", \"confidentialityImpact\": \"HIGH\", \"integrityImpact\": \"NONE\", \"availabilityImpact\": \"NONE\"}, \"exploitabilityScore\": 1.0, \"impactScore\": 3.6}], \"cvssMetricV2\": [{\"source\": \"nvd@nist.gov\", \"type\": \"Primary\", \"cvssData\": {\"version\": \"2.0\", \"vectorString\": \"AV:L/AC:M/Au:N/C:P/I:N/A:N\", \"baseScore\": 1.9, \"accessVector\": \"LOCAL\", \"accessComplexity\": \"MEDIUM\", \"authentication\": \"NONE\", \"confidentialityImpact\": \"PARTIAL\", \"integrityImpact\": \"NONE\", \"availabilityImpact\": \"NONE\"}, \"baseSeverity\": \"LOW\", \"exploitabilityScore\": 3.4, \"impactScore\": 2.9, \"acInsufInfo\": false, \"obtainAllPrivilege\": false, \"obtainUserPrivilege\": false, \"obtainOtherPrivilege\": false, \"userInteractionRequired\": false}]}",
      "published": "2021-10-13T19:15:07.360",
      "references": "[{\"url\": \"https://www.amd.com/en/corporate/product-security/bulletin/amd-sb-1017\", \"source\": \"psirt@amd.com\", \"tags\": [\"Vendor Advisory\"]}, {\"url\": \"https://www.amd.com/en/corporate/product-security/bulletin/amd-sb-1017\", \"source\": \"af854a3a-2127-422b-91ae-364da2661108\", \"tags\": [\"Vendor Advisory\"]}]",
      "sourceIdentifier": "psirt@amd.com",
      "vulnStatus": "Modified",
      "weaknesses": "[{\"source\": \"psirt@amd.com\", \"type\": \"Secondary\", \"description\": [{\"lang\": \"en\", \"value\": \"CWE-208\"}]}, {\"source\": \"nvd@nist.gov\", \"type\": \"Primary\", \"description\": [{\"lang\": \"en\", \"value\": \"CWE-203\"}]}]"
    },
    "nvd": "{\"cve\":{\"id\":\"CVE-2021-26318\",\"sourceIdentifier\":\"psirt@amd.com\",\"published\":\"2021-10-13T19:15:07.360\",\"lastModified\":\"2024-11-21T05:56:05.303\",\"vulnStatus\":\"Modified\",\"cveTags\":[],\"descriptions\":[{\"lang\":\"en\",\"value\":\"A timing and power-based side channel attack leveraging the x86 PREFETCH instructions on some AMD CPUs could potentially result in leaked kernel address space information.\"},{\"lang\":\"es\",\"value\":\"Un ataque de canal lateral basado en el tiempo y la energ\u00eda aprovechando las instrucciones x86 PREFETCH en algunas CPUs de AMD podr\u00eda potencialmente resultar en una filtraci\u00f3n de informaci\u00f3n del espacio de direcciones del kernel\"}],\"metrics\":{\"cvssMetricV31\":[{\"source\":\"nvd@nist.gov\",\"type\":\"Primary\",\"cvssData\":{\"version\":\"3.1\",\"vectorString\":\"CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:N/A:N\",\"baseScore\":4.7,\"baseSeverity\":\"MEDIUM\",\"attackVector\":\"LOCAL\",\"attackComplexity\":\"HIGH\",\"privilegesRequired\":\"LOW\",\"userInteraction\":\"NONE\",\"scope\":\"UNCHANGED\",\"confidentialityImpact\":\"HIGH\",\"integrityImpact\":\"NONE\",\"availabilityImpact\":\"NONE\"},\"exploitabilityScore\":1.0,\"impactScore\":3.6}],\"cvssMetricV2\":[{\"source\":\"nvd@nist.gov\",\"type\":\"Primary\",\"cvssData\":{\"version\":\"2.0\",\"vectorString\":\"AV:L/AC:M/Au:N/C:P/I:N/A:N\",\"baseScore\":1.9,\"accessVector\":\"LOCAL\",\"accessComplexity\":\"MEDIUM\",\"authentication\":\"NONE\",\"confidentialityImpact\":\"PARTIAL\",\"integrityImpact\":\"NONE\",\"availabilityImpact\":\"NONE\"},\"baseSeverity\":\"LOW\",\"exploitabilityScore\":3.4,\"impactScore\":2.9,\"acInsufInfo\":false,\"obtainAllPrivilege\":false,\"obtainUserPrivilege\":false,\"obtainOtherPrivilege\":false,\"userInteractionRequired\":false}]},\"weaknesses\":[{\"source\":\"psirt@amd.com\",\"type\":\"Secondary\",\"description\":[{\"lang\":\"en\",\"value\":\"CWE-208\"}]},{\"source\":\"nvd@nist.gov\",\"type\":\"Primary\",\"description\":[{\"lang\":\"en\",\"value\":\"CWE-203\"}]}],\"configurations\":[{\"operator\":\"AND\",\"nodes\":[{\"operator\":\"OR\",\"negate\":false,\"cpeMatch\":[{\"vulnerable\":true,\"criteria\":\"cpe:2.3:o:amd:athlon_firmware:-:*:*:*:*:*:*:*\",\"matchCriteriaId\":\"ED9F64FB-2B5D-4B9B-9ABD-23324005CB38\"}]},{\"operator\":\"OR\",\"negate\":false,\"cpeMatch\":[{\"vulnerable\":false,\"criteria\":\"cpe:2.3:h:amd:athlon:-:*:*:*:*:*:*:*\",\"matchCriteriaId\":\"2C0A97A7-4790-4234-9617-B88A96C2C2F7\"}]}]},{\"operator\":\"AND\",\"nodes\":[{\"operator\":\"OR\",\"negate\":false,\"cpeMatch\":[{\"vulnerable\":true,\"criteria\":\"cpe:2.3:o:amd:athlon_pro_firmware:-:*:*:*:*:*:*:*\",\"matchCriteriaId\":\"4CDE494B-7C70-4359-856B-793AF93FECE1\"}]},{\"operator\":\"OR\",\"negate\":false,\"cpeMatch\":[{\"vulnerable\":false,\"criteria\":\"cpe:2.3:h:amd:athlon_pro:-:*:*:*:*:*:*:*\",\"matchCriteriaId\":\"464AD06F-B6C1-4F2C-B649-DFA1AE387DD8\"}]}]},{\"operator\":\"AND\",\"nodes\":[{\"operator\":\"OR\",\"negate\":false,\"cpeMatch\":[{\"vulnerable\":true,\"criteria\":\"cpe:2.3:o:amd:epyc_firmware:-:*:*:*:*:*:*:*\",\"matchCriteriaId\":\"33B3CD35-6644-42BD-84C8-D7584178C50E\"}]},{\"operator\":\"OR\",\"negate\":false,\"cpeMatch\":[{\"vulnerable\":false,\"criteria\":\"cpe:2.3:h:amd:epyc:-:*:*:*:*:*:*:*\",\"matchCriteriaId\":\"CF7F2DBC-56AD-4D96-AFB3-5F97FACABDC1\"}]}]},{\"operator\":\"AND\",\"nodes\":[{\"operator\":\"OR\",\"negate\":false,\"cpeMatch\":[{\"vulnerable\":true,\"criteria\":\"cpe:2.3:o:amd:ryzen_firmware:-:*:*:*:*:*:*:*\",\"matchCriteriaId\":\"CAEA5209-C0F6-4645-A541-A68CBC70695B\"}]},{\"operator\":\"OR\",\"negate\":false,\"cpeMatch\":[{\"vulnerable\":false,\"criteria\":\"cpe:2.3:h:amd:ryzen:-:*:*:*:*:*:*:*\",\"matchCriteriaId\":\"047F0F4D-DCE1-4E3F-A888-39E894DF857D\"}]}]},{\"operator\":\"AND\",\"nodes\":[{\"operator\":\"OR\",\"negate\":false,\"cpeMatch\":[{\"vulnerable\":true,\"criteria\":\"cpe:2.3:o:amd:ryzen_pro_firmware:-:*:*:*:*:*:*:*\",\"matchCriteriaId\":\"08E59D0B-FB2F-4C17-B9BC-462DFB366777\"}]},{\"operator\":\"OR\",\"negate\":false,\"cpeMatch\":[{\"vulnerable\":false,\"criteria\":\"cpe:2.3:h:amd:ryzen_pro:-:*:*:*:*:*:*:*\",\"matchCriteriaId\":\"BA9541F0-5B33-4F09-B201-E887DA572571\"}]}]}],\"references\":[{\"url\":\"https://www.amd.com/en/corporate/product-security/bulletin/amd-sb-1017\",\"source\":\"psirt@amd.com\",\"tags\":[\"Vendor Advisory\"]},{\"url\":\"https://www.amd.com/en/corporate/product-security/bulletin/amd-sb-1017\",\"source\":\"af854a3a-2127-422b-91ae-364da2661108\",\"tags\":[\"Vendor Advisory\"]}]}}",
    "redhat_vex": {
      "current_release_date": "2026-03-27T14:29:56+00:00",
      "cve": "CVE-2021-26318",
      "id": "CVE-2021-26318",
      "initial_release_date": "2021-10-12T00:00:00+00:00",
      "product_status:known_not_affected": "1",
      "source": "Red Hat CSAF VEX",
      "status": "final",
      "title": "Side-channels Related to the x86 PREFETCH Instruction",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2021/cve-2021-26318.json",
      "version": "3"
    },
    "suse_vex": {
      "aggregate_severity": "moderate",
      "current_release_date": "2026-07-25T17:42:28Z",
      "cve": "CVE-2021-26318",
      "id": "CVE-2021-26318",
      "initial_release_date": "2023-02-15T03:44:51Z",
      "product_status:known_not_affected": "316",
      "product_status:recommended": "1",
      "source": "SUSE CSAF VEX",
      "status": "interim",
      "title": "SUSE CVE CVE-2021-26318",
      "url": "https://ftp.suse.com/pub/projects/security/csaf-vex/cve-2021-26318.json",
      "version": "14"
    }
  }
}



Log in or create an account to share your comment.




Tags
Taxonomy of the tags.





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.


Detection rules are retrieved from Rulezet.


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.