CVE-2021-28702

2021-10-0613:13:21

XEN

www.cve.org

pci devices

rmrrs

iommu configuration

memory corruption

AI Score

8.3

Confidence

High

EPSS

0.002

Percentile

64.6%

JSON

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.

CNA Affected

[
  {
    "product": "xen",
    "vendor": "Xen",
    "versions": [
      {
        "lessThan": "4.12",
        "status": "unknown",
        "version": "unspecified",
        "versionType": "custom"
      },
      {
        "lessThan": "unspecified",
        "status": "affected",
        "version": "4.12.x",
        "versionType": "custom"
      },
      {
        "lessThan": "unspecified",
        "status": "unaffected",
        "version": "next of xen-unstable",
        "versionType": "custom"
      }
    ]
  }
]