CVE-2021-28701
Published: 8 September 2021
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.
Notes
| Author | Note |
|---|---|
| mdeslaur | hypervisor packages are in universe. For issues in the hypervisor, add appropriate tags to each section, ex: Tags_xen: universe-binary |
Priority
Status
| Package | Release | Status |
|---|---|---|
|
xen Launchpad, Ubuntu, Debian |
bionic |
Needs triage
|
| focal |
Needs triage
|
|
| hirsute |
Ignored
(end of life)
|
|
| impish |
Ignored
(end of life)
|
|
| jammy |
Needs triage
|
|
| kinetic |
Ignored
(end of life, was needs-triage)
|
|
| lunar |
Ignored
(end of life, was needs-triage)
|
|
| mantic |
Needs triage
|
|
| trusty |
Does not exist
|
|
| upstream |
Needs triage
|
|
| xenial |
Needs triage
|
|
| Binaries built from this source package are in Universe and so are supported by the community. | ||
Severity score breakdown
| Parameter | Value |
|---|---|
| Base score | 7.8 |
| Attack vector | Local |
| Attack complexity | High |
| Privileges required | Low |
| User interaction | None |
| Scope | Changed |
| Confidentiality | High |
| Integrity impact | High |
| Availability impact | High |
| Vector | CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:H |