Vulnerability · Published Oct 6, 2021 · Assigned by XEN
CVE-2021-28702
High 7.6
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 0.4% (higher than 39% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Official description
PCI devices with RMRRs not deassigned correctly Certain PCI devices in a system might be assigned Reserved Memory Regions (specified via Reserved Memory Region Reporting, "RMRR"). These are typically used for platform tasks such as legacy USB emulation. If such a device is passed through to a guest, then on guest shutdown the device is not properly deassigned. The IOMMU configuration for these devices which are not properly deassigned ends up pointing to a freed data structure, including the IO Pagetables. Subsequent DMA or interrupts from the device will have unpredictable behaviour, ranging from IOMMU faults to memory corruption.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Alpine:v3.20 | xen | 4.15.1-r1 | ALPINE-CVE-2021-28702 |
| Alpine:v3.21 | xen | 4.15.1-r1 | ALPINE-CVE-2021-28702 |
| Alpine:v3.22 | xen | 4.15.1-r1 | ALPINE-CVE-2021-28702 |
| Alpine:v3.23 | xen | 4.15.1-r1 | ALPINE-CVE-2021-28702 |
| Alpine:v3.24 | xen | 4.15.1-r1 | ALPINE-CVE-2021-28702 |
| Debian:12 | xen | 4.14.3+32-g9de3671772-1 | DEBIAN-CVE-2021-28702 |
| Debian:13 | xen | 4.14.3+32-g9de3671772-1 | DEBIAN-CVE-2021-28702 |
| Debian:14 | xen | 4.14.3+32-g9de3671772-1 | DEBIAN-CVE-2021-28702 |
| Ubuntu:22.04:LTS | xen | no fix listed | UBUNTU-CVE-2021-28702 |
| Ubuntu:24.04:LTS | xen | no fix listed | UBUNTU-CVE-2021-28702 |
| Ubuntu:25.10 | xen | no fix listed | UBUNTU-CVE-2021-28702 |
| Ubuntu:26.04:LTS | xen | no fix listed | UBUNTU-CVE-2021-28702 |
| Ubuntu:26.10 | xen | no fix listed | UBUNTU-CVE-2021-28702 |
Affected products (as reported)
References
- https://xenbits.xenproject.org/xsa/advisory-386.txt x_refsource_MISC
- [oss-security] 20211007 Xen Security Advisory 386 v2 (CVE-2021-28702) - PCI devices with RMRRs not deassigned correctly mailing-list, x_refsource_MLIST
- FEDORA-2021-80bbe7def0 vendor-advisory, x_refsource_FEDORA
- FEDORA-2021-0b7a484688 vendor-advisory, x_refsource_FEDORA
- FEDORA-2021-829f5f2f43 vendor-advisory, x_refsource_FEDORA
- DSA-5017 vendor-advisory, x_refsource_DEBIAN
- GLSA-202208-23 vendor-advisory, x_refsource_GENTOO