{"api_version":"1","generated_at":"2026-05-13T19:22:29+00:00","cve":"CVE-2021-26933","urls":{"html":"https://cve.report/CVE-2021-26933","api":"https://cve.report/api/cve/CVE-2021-26933.json","docs":"https://cve.report/api","cve_org":"https://www.cve.org/CVERecord?id=CVE-2021-26933","nvd":"https://nvd.nist.gov/vuln/detail/CVE-2021-26933"},"summary":{"title":"CVE-2021-26933","description":"An issue was discovered in Xen 4.9 through 4.14.x. On Arm, a guest is allowed to control whether memory accesses are bypassing the cache. This means that Xen needs to ensure that all writes (such as the ones during scrubbing) have reached the memory before handing over the page to a guest. Unfortunately, the operation to clean the cache is happening before checking if the page was scrubbed. Therefore there is no guarantee when all the writes will reach the memory.","state":"PUBLIC","assigner":"cve@mitre.org","published_at":"2021-02-17 02:15:00","updated_at":"2023-11-07 03:31:00"},"problem_types":["NVD-CWE-noinfo"],"metrics":[],"references":[{"url":"https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/4GELN5E6MDR5KQBJF5M5COUUED3YFZTD/","name":"FEDORA-2021-4c819bf1ad","refsource":"","tags":[],"title":"[SECURITY] Fedora 32 Update: xen-4.13.2-7.fc32 - package-announce - Fedora Mailing-Lists","mime":"text/html","httpstatus":"200","archivestatus":"200"},{"url":"https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/EOAJBVAVR6RSCUCHNXPVSNRPSFM7INMP/","name":"FEDORA-2021-47f53a940a","refsource":"","tags":[],"title":"[SECURITY] Fedora 33 Update: xen-4.14.1-5.fc33 - package-announce - Fedora Mailing-Lists","mime":"text/html","httpstatus":"200","archivestatus":"200"},{"url":"https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/EOAJBVAVR6RSCUCHNXPVSNRPSFM7INMP/","name":"FEDORA-2021-47f53a940a","refsource":"FEDORA","tags":["Mailing List","Third Party Advisory"],"title":"[SECURITY] Fedora 33 Update: xen-4.14.1-5.fc33 - package-announce - Fedora Mailing-Lists","mime":"text/html","httpstatus":"200","archivestatus":"0"},{"url":"https://www.debian.org/security/2021/dsa-4888","name":"DSA-4888","refsource":"DEBIAN","tags":[],"title":"Debian -- Security Information -- DSA-4888-1 xen","mime":"text/html","httpstatus":"200","archivestatus":"404"},{"url":"http://xenbits.xen.org/xsa/advisory-364.html","name":"http://xenbits.xen.org/xsa/advisory-364.html","refsource":"MISC","tags":["Patch","Vendor Advisory"],"title":"XSA-364 - Xen Security Advisories","mime":"text/html","httpstatus":"200","archivestatus":"200"},{"url":"https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/4GELN5E6MDR5KQBJF5M5COUUED3YFZTD/","name":"FEDORA-2021-4c819bf1ad","refsource":"FEDORA","tags":["Mailing List","Third Party Advisory"],"title":"[SECURITY] Fedora 32 Update: xen-4.13.2-7.fc32 - package-announce - Fedora Mailing-Lists","mime":"text/html","httpstatus":"200","archivestatus":"404"},{"url":"https://www.cve.org/CVERecord?id=CVE-2021-26933","name":"CVE Program record","refsource":"CVE.ORG","tags":["canonical"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2021-26933","name":"NVD vulnerability detail","refsource":"NVD","tags":["canonical","analysis"]}],"affected":[],"timeline":[],"solutions":[],"workarounds":[],"exploits":[],"credits":[],"nvd_cpes":[{"cve_year":"2021","cve_id":"26933","vulnerable":"1","versionEndIncluding":"","cpe1":"cpe","cpe2":"2.3","cpe3":"o","cpe4":"debian","cpe5":"debian_linux","cpe6":"10.0","cpe7":"*","cpe8":"*","cpe9":"*","cpe10":"*","cpe11":"*","cpe12":"*","cpe13":"*"},{"cve_year":"2021","cve_id":"26933","vulnerable":"1","versionEndIncluding":"","cpe1":"cpe","cpe2":"2.3","cpe3":"o","cpe4":"fedoraproject","cpe5":"fedora","cpe6":"32","cpe7":"*","cpe8":"*","cpe9":"*","cpe10":"*","cpe11":"*","cpe12":"*","cpe13":"*"},{"cve_year":"2021","cve_id":"26933","vulnerable":"1","versionEndIncluding":"","cpe1":"cpe","cpe2":"2.3","cpe3":"o","cpe4":"fedoraproject","cpe5":"fedora","cpe6":"33","cpe7":"*","cpe8":"*","cpe9":"*","cpe10":"*","cpe11":"*","cpe12":"*","cpe13":"*"},{"cve_year":"2021","cve_id":"26933","vulnerable":"1","versionEndIncluding":"1","cpe1":"cpe","cpe2":"2.3","cpe3":"o","cpe4":"fedoraproject","cpe5":"fedora","cpe6":"32","cpe7":"*","cpe8":"*","cpe9":"*","cpe10":"*","cpe11":"*","cpe12":"*","cpe13":"*"},{"cve_year":"2021","cve_id":"26933","vulnerable":"1","versionEndIncluding":"1","cpe1":"cpe","cpe2":"2.3","cpe3":"o","cpe4":"fedoraproject","cpe5":"fedora","cpe6":"33","cpe7":"*","cpe8":"*","cpe9":"*","cpe10":"*","cpe11":"*","cpe12":"*","cpe13":"*"},{"cve_year":"2021","cve_id":"26933","vulnerable":"1","versionEndIncluding":"4.14.1","cpe1":"cpe","cpe2":"2.3","cpe3":"o","cpe4":"xen","cpe5":"xen","cpe6":"*","cpe7":"*","cpe8":"*","cpe9":"*","cpe10":"*","cpe11":"*","cpe12":"arm","cpe13":"*"}],"vendor_comments":[],"enrichments":{"kev":null,"epss":null,"legacy_qids":[{"cve":"CVE-2021-26933","qid":"178530","title":"Debian Security Update for xen (DSA 4888-1)"},{"cve":"CVE-2021-26933","qid":"179495","title":"Debian Security Update for xen (CVE-2021-26933)"},{"cve":"CVE-2021-26933","qid":"500798","title":"Alpine Linux Security Update for xen"},{"cve":"CVE-2021-26933","qid":"501517","title":"Alpine Linux Security Update for xen"},{"cve":"CVE-2021-26933","qid":"501794","title":"Alpine Linux Security Update for xen"},{"cve":"CVE-2021-26933","qid":"504541","title":"Alpine Linux Security Update for xen"}]},"source_records":{"cve_program":{"CVE_data_meta":{"ASSIGNER":"cve@mitre.org","ID":"CVE-2021-26933","STATE":"PUBLIC"},"affects":{"vendor":{"vendor_data":[{"product":{"product_data":[{"product_name":"n/a","version":{"version_data":[{"version_value":"n/a"}]}}]},"vendor_name":"n/a"}]}},"data_format":"MITRE","data_type":"CVE","data_version":"4.0","description":{"description_data":[{"lang":"eng","value":"An issue was discovered in Xen 4.9 through 4.14.x. On Arm, a guest is allowed to control whether memory accesses are bypassing the cache. This means that Xen needs to ensure that all writes (such as the ones during scrubbing) have reached the memory before handing over the page to a guest. Unfortunately, the operation to clean the cache is happening before checking if the page was scrubbed. Therefore there is no guarantee when all the writes will reach the memory."}]},"problemtype":{"problemtype_data":[{"description":[{"lang":"eng","value":"n/a"}]}]},"references":{"reference_data":[{"url":"http://xenbits.xen.org/xsa/advisory-364.html","refsource":"MISC","name":"http://xenbits.xen.org/xsa/advisory-364.html"},{"refsource":"FEDORA","name":"FEDORA-2021-4c819bf1ad","url":"https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/4GELN5E6MDR5KQBJF5M5COUUED3YFZTD/"},{"refsource":"FEDORA","name":"FEDORA-2021-47f53a940a","url":"https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/EOAJBVAVR6RSCUCHNXPVSNRPSFM7INMP/"},{"refsource":"DEBIAN","name":"DSA-4888","url":"https://www.debian.org/security/2021/dsa-4888"}]}},"nvd":{"publishedDate":"2021-02-17 02:15:00","lastModifiedDate":"2023-11-07 03:31:00","problem_types":["NVD-CWE-noinfo"],"metrics":{"baseMetricV3":{"cvssV3":{"version":"3.1","vectorString":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N","attackVector":"LOCAL","attackComplexity":"LOW","privilegesRequired":"LOW","userInteraction":"NONE","scope":"UNCHANGED","confidentialityImpact":"HIGH","integrityImpact":"NONE","availabilityImpact":"NONE","baseScore":5.5,"baseSeverity":"MEDIUM"},"exploitabilityScore":1.8,"impactScore":3.6},"baseMetricV2":{"cvssV2":{"version":"2.0","vectorString":"AV:L/AC:L/Au:N/C:P/I:N/A:N","accessVector":"LOCAL","accessComplexity":"LOW","authentication":"NONE","confidentialityImpact":"PARTIAL","integrityImpact":"NONE","availabilityImpact":"NONE","baseScore":2.1},"severity":"LOW","exploitabilityScore":3.9,"impactScore":2.9,"acInsufInfo":false,"obtainAllPrivilege":false,"obtainUserPrivilege":false,"obtainOtherPrivilege":false,"userInteractionRequired":false}},"configurations":{"CVE_data_version":"4.0","nodes":[{"operator":"OR","children":[],"cpe_match":[{"vulnerable":true,"cpe23Uri":"cpe:2.3:o:xen:xen:*:*:*:*:*:*:arm:*","versionStartIncluding":"4.9.0","versionEndIncluding":"4.14.1","cpe_name":[]}]},{"operator":"OR","children":[],"cpe_match":[{"vulnerable":true,"cpe23Uri":"cpe:2.3:o:fedoraproject:fedora:32:*:*:*:*:*:*:*","cpe_name":[]},{"vulnerable":true,"cpe23Uri":"cpe:2.3:o:fedoraproject:fedora:33:*:*:*:*:*:*:*","cpe_name":[]}]},{"operator":"OR","children":[],"cpe_match":[{"vulnerable":true,"cpe23Uri":"cpe:2.3:o:debian:debian_linux:10.0:*:*:*:*:*:*:*","cpe_name":[]}]}]}},"legacy_mitre":{"record":{"CveYear":"2021","CveId":"26933","Ordinal":"202015","Title":"CVE-2021-26933","CVE":"CVE-2021-26933","Year":"2021"},"notes":[{"CveYear":"2021","CveId":"26933","Ordinal":"1","NoteData":"An issue was discovered in Xen 4.9 through 4.14.x. On Arm, a guest is allowed to control whether memory accesses are bypassing the cache. This means that Xen needs to ensure that all writes (such as the ones during scrubbing) have reached the memory before handing over the page to a guest. Unfortunately, the operation to clean the cache is happening before checking if the page was scrubbed. Therefore there is no guarantee when all the writes will reach the memory.","Type":"Description","Title":null},{"CveYear":"2021","CveId":"26933","Ordinal":"2","NoteData":"2021-02-16","Type":"Other","Title":"Published"},{"CveYear":"2021","CveId":"26933","Ordinal":"3","NoteData":"2021-04-11","Type":"Other","Title":"Modified"}]}}}