Vulnerability · Published Nov 21, 2021 · Assigned by XEN
CVE-2021-28710
High 8.8
In plain English
A high-severity security flaw in xen from Xen. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.3% (higher than 21% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Official 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.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Alpine:v3.20 | xen | 4.15.1-r1 | ALPINE-CVE-2021-28710 |
| Alpine:v3.21 | xen | 4.15.1-r1 | ALPINE-CVE-2021-28710 |
| Alpine:v3.22 | xen | 4.15.1-r1 | ALPINE-CVE-2021-28710 |
| Alpine:v3.23 | xen | 4.15.1-r1 | ALPINE-CVE-2021-28710 |
| Alpine:v3.24 | xen | 4.15.1-r1 | ALPINE-CVE-2021-28710 |
Affected products (as reported)
References
- https://xenbits.xenproject.org/xsa/advisory-390.txt x_refsource_MISC
- FEDORA-2021-03645e9807 vendor-advisory, x_refsource_FEDORA
- GLSA-202208-23 vendor-advisory, x_refsource_GENTOO