CVE-2021-28710
Published: 21 November 2021
certain VT-d IOMMUs may not work in shared page table mode For efficiency reasons, address translation control structures (page tables) may (and, on suitable hardware, by default will) be shared between CPUs, for second-level translation (EPT), and IOMMUs. These page tables are presently set up to always be 4 levels deep. However, an IOMMU may require the use of just 3 page table levels. In such a configuration the lop level table needs to be stripped before inserting the root table's address into the hardware pagetable base register. When sharing page tables, Xen erroneously skipped this stripping. Consequently, the guest is able to write to leaf page table entries.
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 |
Not vulnerable
|
| focal |
Not vulnerable
|
|
| hirsute |
Not vulnerable
|
|
| impish |
Not vulnerable
|
|
| jammy |
Not vulnerable
|
|
| trusty |
Does not exist
|
|
| upstream |
Not vulnerable
(debian: Only affects 4.15 series)
|
|
| xenial |
Not vulnerable
|
|
| Binaries built from this source package are in Universe and so are supported by the community. | ||
Severity score breakdown
| Parameter | Value |
|---|---|
| Base score | 8.8 |
| Attack vector | Local |
| Attack complexity | Low |
| Privileges required | Low |
| User interaction | None |
| Scope | Changed |
| Confidentiality | High |
| Integrity impact | High |
| Availability impact | High |
| Vector | CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H |