CVE-2021-28710
mediumpriority · track · 35EPSS 0.003 · 21 %ileEURUUSEPSS · scored 2026-10-27
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.
cvss
Technical severity, 0–10. One row per scoring source.
base score 0–10 · higher = more severe · hover a vector to decode⚠ sources disagree · medium–high · 6.9–8.8
weaknesses
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affected products (6)
Products and version ranges known to be affected.
also known as (4)
Other names and identifiers for this entity.
sources
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references (14)
External citations — patches, advisories, analysis.
- https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/I7ZGWVVRI4XY2XSTBI3XEMWBXPDVX6OT/cnnvd
- https://nvd.nist.gov/vuln/detail/CVE-2021-28710cnnvd
- https://packetstormsecurity.com/files/168076/Gentoo-Linux-Security-Advisory-202208-23.htmlcnnvd
- https://security.gentoo.org/glsa/202208-23cnnvd
- https://vigilance.fr/vulnerability/Xen-privilege-escalation-via-VT-d-IOMMUs-Shared-Page-Table-Mode-36934cnnvd
- https://www.auscert.org.au/bulletins/ESB-2021.3966cnnvd
- https://www.cybersecurity-help.cz/vdb/SB2021112208cnnvd
- https://xenbits.xenproject.org/xsa/advisory-390.txtcnnvd
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