{"id":"DEBIAN-CVE-2021-28701","details":"Another race in XENMAPSPACE_grant_table handling Guests are permitted access to certain Xen-owned pages of memory. The majority of such pages remain allocated / associated with a guest for its entire lifetime. Grant table v2 status pages, however, are de-allocated when a guest switches (back) from v2 to v1. Freeing such pages requires that the hypervisor enforce that no parallel request can result in the addition of a mapping of such a page to a guest. That enforcement was missing, allowing guests to retain access to pages that were freed and perhaps re-used for other purposes. Unfortunately, when XSA-379 was being prepared, this similar issue was not noticed.","modified":"2026-09-15T09:01:33.130945277Z","published":"2021-09-08T14:15:08.547Z","upstream":["CVE-2021-28701"],"references":[{"type":"ADVISORY","url":"https://security-tracker.debian.org/tracker/CVE-2021-28701"}],"affected":[{"package":{"name":"xen","ecosystem":"Debian:12","purl":"pkg:deb/debian/xen?arch=source&distro=bookworm"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"4.14.3-1"}]}],"ecosystem_specific":{"urgency":"not yet assigned"},"database_specific":{"source":"https://storage.googleapis.com/osv-test-debian-osv/debian-cve-osv/DEBIAN-CVE-2021-28701.json"}},{"package":{"name":"xen","ecosystem":"Debian:13","purl":"pkg:deb/debian/xen?arch=source&distro=trixie"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"4.14.3-1"}]}],"ecosystem_specific":{"urgency":"not yet assigned"},"database_specific":{"source":"https://storage.googleapis.com/osv-test-debian-osv/debian-cve-osv/DEBIAN-CVE-2021-28701.json"}},{"package":{"name":"xen","ecosystem":"Debian:14","purl":"pkg:deb/debian/xen?arch=source&distro=forky"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"4.14.3-1"}]}],"ecosystem_specific":{"urgency":"not yet assigned"},"database_specific":{"source":"https://storage.googleapis.com/osv-test-debian-osv/debian-cve-osv/DEBIAN-CVE-2021-28701.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:H"}]}