CVE-2021-28701
HIGH7.8EPSS 0.06%Published: 9/8/2021Modified: 4/28/2026
Also known as:ALPINE-CVE-2021-28701DEBIAN-CVE-2021-28701
Description
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.
Affected packages (2)
- Alpine/xenfrom 0, < 4.13.3-r3
- Debian/xenfrom 0, < 4.14.3-1~deb11u1
CVSS scores
| Source | Version | Severity | Vector |
|---|---|---|---|
| osv | CVSS 3.1 | HIGH7.8 | CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:H |