{"id":"CVE-2026-21510","url":"https://www.cyber-defence.io/tools/cve/CVE-2026-21510","generatedAt":"2026-10-31T06:00:39.458Z","title":"Microsoft Windows Shell Protection Mechanism Failure Vulnerability","description":"Protection mechanism failure in Windows Shell allows an unauthorized attacker to bypass a security feature over a network.","published":"2026-02-10T18:16:33.000Z","lastModified":"2026-06-17T10:18:45.000Z","status":"Analyzed","sourceIdentifier":"secure@microsoft.com","cvss":{"version":"3.1","score":8.8,"severity":"HIGH","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H"},"cwe":["CWE-693"],"affected":["microsoft/windows 10 1607","microsoft/windows 10 1809","microsoft/windows 10 21h2","microsoft/windows 10 22h2","microsoft/windows 11 23h2","microsoft/windows 11 24h2","microsoft/windows 11 25h2","microsoft/windows server 2012","microsoft/windows server 2016","microsoft/windows server 2019","microsoft/windows server 2022","microsoft/windows server 2022 23h2","microsoft/windows server 2025"],"epss":{"score":0.61238,"percentile":0.9916,"date":"2026-10-30","history":[{"date":"2026-09-26","score":0.24226,"percentile":0.97782},{"date":"2026-10-25","score":0.61238,"percentile":0.99155}]},"kev":{"listed":true,"dateAdded":"2026-02-10","dueDate":"2026-03-03","knownRansomwareCampaignUse":"Unknown","notes":"Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.\nhttps://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-21510 ; https://nvd.nist.gov/vuln/detail/CVE-2026-21510 "},"exploits":{"count":0,"verified":false,"firstPublished":null,"source":"Exploit-DB (https://gitlab.com/exploit-database/exploitdb)","entries":[]},"verdict":{"level":"urgent","text":"Known to be exploited in the wild (CISA KEV, CISA remediation deadline 3 March 2026). Treat as an emergency change: patch or isolate now, then hunt for prior compromise."},"changes":[{"kind":"epss","label":"EPSS jump","at":"2026-10-25T00:00:00.000Z","detail":{"to":0.61238,"from":0.24537,"percentile":0.99155},"summary":"EPSS moved from 24.5% to 61.2% probability of exploitation in the next thirty days."}],"references":[{"url":"https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-21510","tags":["Vendor Advisory"],"source":"secure@microsoft.com"},{"url":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2026-21510","tags":["US Government Resource"],"source":"134c704f-9b21-4f2e-91b3-4a467353bcc0"}],"sources":{"nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-21510","epss":"https://www.first.org/epss/","kev":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog","exploitdb":"https://www.exploit-db.com/"},"licence":"CC BY 4.0 — link back to the CVE Explorer if you publish the results; upstream data remains subject to its own terms."}