Attacker Value
Unknown
(0 users assessed)
Exploitability
Unknown
(0 users assessed)
User Interaction
None
Privileges Required
Low
Attack Vector
Local
0

CVE-2021-28710

Disclosure Date: November 21, 2021
Add MITRE ATT&CK tactics and techniques that apply to this CVE.

Description

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.

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CVSS V3 Severity and Metrics
Base Score:
8.8 High
Impact Score:
6
Exploitability Score:
2
Vector:
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H
Attack Vector (AV):
Local
Attack Complexity (AC):
Low
Privileges Required (PR):
Low
User Interaction (UI):
None
Scope (S):
Changed
Confidentiality (C):
High
Integrity (I):
High
Availability (A):
High

General Information

Vendors

  • fedoraproject,
  • xen

Products

  • fedora 35,
  • xen 4.15.0

Additional Info

Technical Analysis