{"id":"CVE-2026-21248","url":"https://www.cyber-defence.io/tools/cve/CVE-2026-21248","generatedAt":"2026-10-28T00:15:17.085Z","title":"Heap-based buffer overflow in Windows Hyper-V allows an authorized attacker to execute code locally.","description":"Heap-based buffer overflow in Windows Hyper-V allows an authorized attacker to execute code locally.","published":"2026-02-10T18:16:26.000Z","lastModified":"2026-06-17T10:18:22.000Z","status":"Analyzed","sourceIdentifier":"secure@microsoft.com","cvss":{"version":"3.1","score":7.3,"severity":"HIGH","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:R/S:U/C:H/I:H/A:H"},"cwe":["CWE-122","CWE-787"],"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 2016","microsoft/windows server 2019","microsoft/windows server 2022","microsoft/windows server 2022 23h2","microsoft/windows server 2025"],"epss":{"score":0.01327,"percentile":0.70787,"date":"2026-10-26","history":[]},"kev":{"listed":false},"exploits":{"count":1,"verified":false,"firstPublished":"2026-04-30","source":"Exploit-DB (https://gitlab.com/exploit-database/exploitdb)","entries":[{"edbId":52537,"kind":"exploit","title":"Windows 11 25H2  - Heap Overflow","url":"https://www.exploit-db.com/exploits/52537","sourceUrl":"https://gitlab.com/exploit-database/exploitdb/-/blob/main/exploits/windows/local/52537.txt","file":"exploits/windows/local/52537.txt","published":"2026-04-30","added":"2026-04-30","updated":"2026-04-30","author":"nu11secur1ty","type":"local","platform":"windows","port":null,"verified":false,"codes":["CVE-2026-21248","CVE-2026-21244"],"tags":null,"aliases":null,"applicationUrl":null,"screenshotUrl":null,"referenceUrl":null}]},"verdict":{"level":"urgent","text":"A public exploit is published in Exploit-DB and the impact is high, while EPSS rates exploitation at 1.3%. Anyone can run this; patch or mitigate before the next change window and check exposed instances for signs of use."},"changes":[],"references":[{"url":"https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-21248","tags":["Vendor Advisory"],"source":"secure@microsoft.com"}],"sources":{"nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-21248","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."}