{"id":"CVE-2021-28688","url":"https://www.cyber-defence.io/tools/cve/CVE-2021-28688","generatedAt":"2026-10-27T23:29:46.028Z","title":"The lack of cleanup would result in leaking persistent grants.","description":"The fix for XSA-365 includes initialization of pointers such that subsequent cleanup code wouldn't use uninitialized or stale values. This initialization went too far and may under certain conditions also overwrite pointers which are in need of cleaning up. The lack of cleanup would result in leaking persistent grants. The leak in turn would prevent fully cleaning up after a respective guest has died, leaving around zombie domains. All Linux versions having the fix for XSA-365 applied are vulnerable. XSA-365 was classified to affect versions back to at least 3.11.","published":"2021-04-06T19:15:15.000Z","lastModified":"2026-06-17T03:46:48.000Z","status":"Modified","sourceIdentifier":"security@xen.org","cvss":{"version":"3.1","score":6.5,"severity":"MEDIUM","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:N/I:N/A:H"},"cwe":["CWE-665"],"affected":["linux/linux kernel","debian/debian linux"],"epss":{"score":0.0034,"percentile":0.27201,"date":"2026-10-26","history":[]},"kev":{"listed":false},"exploits":{"count":0,"verified":false,"firstPublished":null,"source":"Exploit-DB (https://gitlab.com/exploit-database/exploitdb)","entries":[]},"verdict":{"level":"low","text":"Lower severity and a low EPSS score (0.34%). Track it; it rarely justifies an emergency change on its own."},"changes":[],"references":[{"url":"https://lists.debian.org/debian-lts-announce/2021/06/msg00019.html","tags":["Third Party Advisory"],"source":"security@xen.org"},{"url":"https://lists.debian.org/debian-lts-announce/2021/06/msg00020.html","tags":["Third Party Advisory"],"source":"security@xen.org"},{"url":"https://xenbits.xenproject.org/xsa/advisory-371.txt","tags":["Patch","Third Party Advisory"],"source":"security@xen.org"},{"url":"https://lists.debian.org/debian-lts-announce/2021/06/msg00019.html","tags":["Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://lists.debian.org/debian-lts-announce/2021/06/msg00020.html","tags":["Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://xenbits.xenproject.org/xsa/advisory-371.txt","tags":["Patch","Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"}],"sources":{"nvd":"https://nvd.nist.gov/vuln/detail/CVE-2021-28688","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."}